Final reportTracking And Positioning Of Mobile System In Telecommunication Networks

Tracking And Positioning Of Mobile System In Telecommunication NetworksTracking And Positioning Of Mobile System In Telecommunication Networks

CHAPTER 1

INTRODUCTION

1.1 MOBILE TRACKING

Mobile phone trcking refers to the attaining of the current position of a mobile

phone, stationary or moving. Localization may ocuur either via multilateration of

radio signals between (several) radio towers of the network and the phone, or simply

via GPS. To locate the phone using multilateration of radio signals,ti must emit at

least the roaming signal to contact the next nearby antenna tower, but the process

does not require an active call.

1.2 POSITIONING

Mobile positioning refers to technology used by telecommunication companies to

approximate the location of a mobile phone.

1.3 INTRODUCTION TO MOBILE TECHNOLOGY

Fig 1.1: Configuration of a typical mobile telecommunication network.

As shown in Fig 1.1, the mobile telecommunication network includes a several base

stations (BSs) T 1to T N for providing mobile telecommunication service to a mobile

Tracking and positioning of mobile system in telecommunication networks

subscriber through a mobile telephone M1, a base station controller (BSC) for controlling

the BSs T 1 to T N, and a mobile telephone switching office (MTSO) for connecting the

BSC to another BTS or a PSTN (Public Switched Telephone Network).

In a cellular mobile telecommunication network, the whole service area is divided into a

several coverage areas having respective base stations (BS). Each BS coverage area is

called a "cell" Each BS is provided with a frequency of a range between 450 to900 MHz.

More than one cells can use same frequency. Only condition is that two adjacent cells

must have different frequencies. An MTSO controls these BSs so that a subscriber can

continue his call without interruption while moving between different cells. The MTSO

can reduce the time required for calling a subscriber by locating the cell of the subscriber.

In case of an emergency like a fire, or a patient needing first aid treatment, the mobile

subscriber should be accurately located.

“Tracking the location of a mobile subscriber within the boundary of a cell in a mobile

telecommunication network is known as "location based services.”

Mobile technology includes mainly two functions. They are call fixing and hands-off

process. 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 search for the strongest 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 searches where the subscriber is and connects the call.

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 processes geolocation (Postioning) of

the mobile unit is essential.

Department of ECE, CEC Benjanapadavu 1


CHAPTER 2

NEED FOR MOBILE TRACKING

Recent demands from new applications require positioning capabilities of mobile

telephones or other devices. The ability to obtain the geo-location of the Mobile

Telephone (MT) in the cellular system allows the network operators to facilitate new

services to the mobile users. The most immediate motivation for the cellular system to

provide Mobile Telephone position is enhanced in accident emergency services. The

positioning of the mobile user could provide services like

Emergency service for subscriber safety.

Tracking criminal and stolen mobile

Location based services

Location sensitive billing.

Cellular Fraud detection.

Traffic information

Intelligent transport system services.

Efficient and effective network performance and management.



CHAPTER 3

POSITIONING TECHNIQUES

Positioning technique classified on where the data is crossed

Mobile (Handset) based positioning

Direction based positioning

Distance based positioning

3.1 MOBILE BASED POSITIONING:

There is two types of mobile based positioning:

1. Global positioning system (GPS)

2. Cell identity

3.1.1 Global Positioning System (GPS)

A mobile telephone can be located by a mobile telephone itself or through a mobile

telecommunication network. To locate the mobile telephone by itself, the mobile

telephone is provided with a GPS receiver to calculate its location in latitude and

longitude coordinates based on the location information received from a satellite through

the GPS receiver.

A method called Trilateration is used to find the exact location of a mobile. Trilateration

takes the known distances from three different objects and finds out where you are with

respect to objects. Intersection of three circles gives the exact position of the mobile as

show in the subsequent fig 3.1



Fig 3.1: Trilateration

Fig.3.2: Global positioning system

Disadvantage of GPS based positioning:

Increases the price and the size of the mobile telephone.

The load on the mobile telephone is increased.

Power consumption is high.

3.1.2 Cell identity

Most simplistic and cost-effective way to provide position information. Simply

determines which cell of wireless network the device is using. Since BS for each cell is

fixed,cell identity can easily translated into the location of a mobile user. Gives the

general location of where the user is but not the exact location.

The ways to improve the accuracy of cell identity is by dividing the cell into sectors

(either 120 degree or 60 degree), thereby reducing the total area of a possible location.



Fig. 3.3: Cell Identity

3.2 DIRECTION BASED POSITIONING

3.2.1 Angle of Arrival (AOA)

This method calculates the angle of arrival of signal receiving at the BS. When a mobile

user switches the system ON it receives the signal from different base stations, may be 3

or 4 or more. The angle of arrival method 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.

Angle of arrival method is not an accurate method used for the mobile positioning

because of its some disadvantages such as:



Fig 3.4: Angle Of Arrival

• The determination of the system will be in error if the angle of incidence is

changed due to any obstacle like atmospheric particles or due to scattering etc.

• The accurate location cannot be determined if the mobile user is in between the

BSs, that is in a straight line.

• It cannot be used for the indoor environments.

The accuracy of the method can be increased by increasing the number of the base

stations used for determination. The direction based mobile positioning is not used

commonly now a day. It is replaced by the distance based mobile positioning

technologies.

3.3 DISTANCE BASED MOBILE POSITIONING

In the case that the mobile telephone network locates the mobile telephone, at least three

base stations (BSs) receive a signal from the mobile telephone; calculate the distances

between the Base Stations and the mobile telephone, using the arrival time of the signals

at the BSs, then determine the location of the mobile telephone using the trigonometry.

This location service is provided generally by a location data processor included in a base

station controller (BSC). Upon a request for service about the location of a specific

mobile subscriber, the BSC selects the three adjacent BSs surrounding the mobile



telephone for use in the location service, and these selected BSs are ready for

communication with the mobile telephone.

3.3.1 Time of Arrival (TOA)

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

Time Of Arrival of a signal transmitted from the mobile telephone at the BS. It is

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

having the radius of the distances between the BSs and the mobile telephone.

The distance is calculated by the following equation :

Ri = C τi = sqrt ( (xi – X ) 2 + (yi – Y) 2 )……………………..3.1

Where,C – Propagation speed of electromagnetic wave,

τi – propagation of time from the MT to ith BS,

Xi, yi -- location of ith base station,

X, Y – mobile position.

Fig. 3.5: illustrates a typical TOA method for locating a MT

As shown in Fig 3.5, three circles C1, C2, and C3, whose radii are the distance between the

mobile telephone M1 and atleast three BSs T1, T2, and T3, are overlapped across an area.

The mobile telephone M1 is located in the overlap area.

One approach to locating the mobile telephone M1 in the overlap area 1 is to use a

common chord, as shown in Fig 3.5 When at least three circles 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

TOA 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 approximate equal

distance from the selected BSs and in a similar propagation environment to each

respective BS.

3.2.2 Time Difference of Arrival (TDOA)

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.

The implementation requires accurate synchronization of each BS.

The signal of the mobile telephone often travels a longer path to a BS due to the

multi-path fading characteristic and the Non- Line Of Sight (NLOS) effects.

In this method, three circles or hyperbolas do not meet at one point but overlap

each other over an area.

Fig 3.6: Illustrates the TDOA method of locating a mobile telephone.

In the case that a first mobile telephone M1 is nearer to the first BS T1, as shown in

Fig 3.6, the procedure will be described by a way of example.

In Fig 3.6, two circles C11 and C21 are drawn based on the TOAs of a signal transmitted

from the first mobile telephone M1 at the first and the second BSs T1 and T2. A first



common chord L1 is defined by the intersection between the circles C11 and C21. But if the

path between the first mobile telephone M1 and the second BS T2 is in an NLOS condition

and 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 left from the actual location of

the mobile telephone M1.

The effect is the same in the opposite case. If the path between the first mobile telephone

M1 and the second BS T2 is in the LOS condition and the path between the first mobile

telephone M1 and the first BS T1 is in the NLOS condition, the common chord L1 is also

far right from the actual location of the mobile telephone M1. In this method using a

common chord involves a huge location error unless the paths between the mobile

telephone and each BS have the same propagation environment.



CHAPTER 4

LOCATION TRACKING CURVE METHOD

4.1 PROPOSAL

The method proposed by us for tracking the location of a mobile telephone using curves

connecting the points where circles intersect one another, the circles radii being the

distances between BSs and the mobile telephone. The steps involved are:

Fig 4.1: Flowchart showing the steps involved in locating a mobile telephone

a. Each base station nearer to a mobile telephone receives a predetermined signal

from the mobile telephone and calculates the distance between the mobile

telephone and the base station and the variances of time arrival of the signal at the

base station;

b. A circle is drawn to have a radius being the distance and the coordinates of the

base station being the centre of the circle;



c. Each base station nearer to a mobile telephone receives a predetermined signal

from the mobile telephone and calculates the distance between the mobile

telephone and the base station and the variances of time arrival of the signal at the

base station;

d. A circle is drawn to have a radius being the distance and the coordinates of the

base station being the centre of the circle;

e. A pair of the first and the second base stations is selected among the base

stations. A several location tracking curves connecting two intersection points

between the selected circles corresponding to the first and the second base stations

are drawn. One of the location tracking curves is selected using the variances of

the first and the second base stations;

f. The steps c. and d. are repeated for the other pairs of the base stations;

g. The intersection points are obtained among the location tracking curves selected

in step d. and e. and,

h. The location of the mobile telephone is determined using the coordinates of the

intersection points obtained in step e.

4.2 DESCRIPTION

When a location service is requested about a specific mobile telephone by a user or a

network, the location data processor draws two circles C1 and C2 with their respective

centers set at BSs T1 and T2 based on the TOAs of a signal transmitted from the

corresponding mobile telephone M1 or M2 to the two BSs T1 and T2 located near the

mobile telephone M1 or M2 .The two circles C1 and C2 define a common chord L1.



Fig 4.2: Illustrates a proposed method for mobile telephone location.

However, if each mobile telephone M1 or M2 is placed in a different propagation

environment with respect to the BSs T1 and T2, the location of the mobile telephone M1

or M2 can not be determined by the common chord L1. Therefore, we use location

tracking curves TR1 and TR2 connecting the same two intersection points P1 and P2 of the

two circles C1 and C2, instead of the common chord L1.

The two curves TR1 and TR2 have their middle points intersecting the line ST, which

connects the positions of the two BSs T1 and T2 and the parts of two circles C1 and C2

drawn to connect the two intersection points P1 and P2. Instead of the common chord L1,

the location data processor uses the curve TR1 for the mobile telephone M1 and the curve

TR2 for the mobile telephone M2. It prevents the location error caused by the multi-path

fading or the NLOS path characteristics.

4.3 DETERMINATION OF THE LOCATION TRACKING

CURVE

The BS with smaller variances should be selected to draw reference circles based on the

variances.

Fig 4.3: Illustrates the determination of location tracking curve.

From Fig 4.3, assuming that the first and the second BSs T1 and T2 selected for use in the

location tracking are present at positions (x1, y1) and (x2, y2), respectively, in the second-

dimensional coordinates, the location data processor draws the two circles C1 and C2 with



the coordinates (x1, y1) and (x2, y2) of the two BSs T1 and T2 at their centers The curve

connects the two points P1 and P2 at which the two circles C1 and C2 intersect each other.

The coordinates of the intersection points P1 and P2 are (xA, yA) and (xB, yB), respectively.

Since the mobile telephone is near the first BS T1 with respect to the common chord L1,

the variances of the TOAs of a signal transmitted from the mobile telephone at the first

BS T1 will be larger than those of the signal at the second BS. Therefore, reference circles

TR1 to TR4 are drawn with respect to the second BS T2 with smaller variances, as shown

in Figure 4.3.

The coordinates of the reference circle can be obtained (using minimum variance) which

has its center on the line ST passing through (x1, y1) and (x2, y2) and passes through (xA,

yA) and (xB, yB). Selecting the center of the reference circle is significant as the mobile

telephone is located on the reference circle. The location data processor selects the

desired curves (reference circles) with respect to the several BSs selected for location

tracking. In Figure 4.3, as the real location of the mobile telephone deviates farther from

the circle C2 with the second BS T2 at its center, the center of a reference circle is farther

from the location of the second BS T2. That is, the center of a desired reference circle is

farther from the second BS T2 in the case of a third mobile telephone M3 (curve C3) than

in the case of a fourth mobile telephone M4.

4.4 REFERENCE CIRCLE SELECTION

The variances of the TOAs of a signal which arrives at the two BSs T1 and T2 from

different paths are used to find the curve on which the actual location of the mobile

telephone is determined. If the TOAs of the signal at the first BS T1 from TN propagation

paths are t1, t2, . . . , tN, the first BS T1 calculates the variances σ of t1, t2, . . . , tN. The

location data processor compares the variances calculated by the first BS T1 with the

variances calculated by the second BS T2 and considers that the mobile telephone is near

to that BS with the larger variances (the first BS T2 in Fig 4.3). Hence, the reference circle

has its center near to the BS with the smaller variances (the second BS T2 in Fig 4.3) on

the line ST.With the larger variances, the center of a reference circle gets farther to the

right from the center of the second BS T2. In order to select the desired curve, the location

data processor initializes the reference circles with predetermined radii and the variances

of TOAs of a signal transmitted from the mobile telephone located on the reference

circles, and compare the preset variances with real variance measurements.



The location data processor sets a several reference circles based on the distances

between the mobile telephone and the BS with the smaller variances(the second BS T 2) In

Fig 4.3, as an example, the first to the fourth reference circles TR1 to TR4 have radii twice,

three times, four times, and five times, respectively, of that of BS T2 .where all these

points of reference circles TR1 and TR4 are located along the line ST The variances of the

second BS T2 smaller than those of the first BS T1 are used as a criterion for selecting an

optimal reference circle.

Therefore, the location data processor predetermines the reference variances for the first

to the fourth reference circles TR1 to TR4 to be compared with respect to the second BS

T1. It is assumed in the following description that σ 1, σ 2, and σ 3 are reference variances

and σ 1< σ 2< σ 3

The location data processor compares the variances calculated by the two BSs T1 and T2

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

reference circle. If the selected variances (those of the second BS T2) are σ, the location

data processor compares the selected variances σ, with the preset reference variances σ 1,

σ 2, and σ 3.

If σ <= σ 1, the curve of the first reference circles TR1 is selected.

If σ 1 < σ <= σ 2, the curve of the TR2 is selected.

If σ 2 < σ <= σ 3, the curve of the TR3 is selected.

If σ 3 < σ, the curve of the fourth reference circles TR4 is selected.

As we have seen, the location data processor selects the optimal curve (reference circle)

for the two BSs among the several BSs, and selects another optimal circle for another BS

pair, and so on.

When curves are selected for all selected BS pairs, the location data processor obtains the

intersection points among the selected curves as shown in Figure 4.4. However, as the

selected curves do not intersect at one point due to the multi-path fading or the NLOS

effects, the midpoint of these intersection points is determined as the location of the

mobile telephone.



Fig 4.4: Illustrates the positioning of mobile by the proposed method.

As the three intersection points M1 (xA, yA), M2 (xB, yB), and M3 (xC, yC) are defined by the

three curves TR1 to TR3, the location data processor considers the mobile telephone to be

located at (x, y). While the three BSs are selected for the location service using the TOAs

of a signal arrived at each BS from a mobile telephone has been described in the

embodiment of the present invention, more BSs can be used to increase

the accuracy in locating the exact position of the mobile station. If N th intersection points

are defined by location tracking curves obtained according to the present invention and an

ith intersection point is at (xi, yi), coordinates (x, y) indicate the location of the mobile

telephone.

After the location of the mobile telephone, that is, the intersection points among the

curves are obtained, the location data processor represents the intersection points in the

latitude and the longitude coordinates and transmits the position coordinates to the

network (BS/BSC/MSC) and the mobile telephone.



CHAPTER 5

BLOCKING OF CELL PHONE TRACKING

Many cell phone users don’t know that their phones are inherently traceable due to

advances in GPS and cellular technology. To many this is a welcome safety feature for

emergencies, but there is also a growing concern among those who value privacy in

everyday life. Your best bet is to be educated about how you can be traced and to be very

familiar with the capabilities and features of your phone.

Instructions:

Choose “E911″ in the “location” menu on your phone. On some phones you may

need to enable privacy mode instead. These settings will allow GPS tracking only

in response to a 911 call, which is required by law. Menus are different on all

phones so you may need to consult the owner’s manual if you cannot find location

settings.

Check for physical GPS tracking devices that may be attached to your phone.

Look under the battery, in the battery compartment, and on the outside of the

phone. Remove anything that did not come in the original sealed box or that you

did not attach yourself.

Remove any tracking software that is installed on your handset. If anyone has ever

had your phone for even a few minutes, he may have installed a third-party

application that allows your phone to be tracked. Research any programs that you

cannot identify.

Contact your cellular phone company and inquire about any tracking or

monitoring features that have been enabled on your account. Remove those

features if there are any and set a new password to prevent unauthorized access.

Remove the battery from your phone. This is the only way to guarantee the phone

is untraceable. Cell phone towers can still triangulate your position to some degree

when the phone is on, and “roving bug” software can make your phone a

surveillance device even when the power is off.



CHAPTER 6

ADVANTAGES AND DISADVANTAGES OF

MOBILE TRACKING SYSTEMS

With modern technology it’s now possible to do many things on mobile phones and smart

phones. Apart from the obvious convenience of being able to call colleagues and friends

whilst on the move, smartphones can also be vital tools for use in business and

commerce. But did you know that your smartphone’s built-in GPS receiver can also help

you stay safe, avoid getting lost and find your way to that crucial meeting on time?

By using a combination of GPS data and mobile mast triangulation, your current location

can be established wherever your phone is capable of receiving a signal. Mobile-tracking

technology increases the chances of finding someone quickly. Most cell phones contain

GPS technology, which can establish a person's whereabouts by calculating the location,

speed and time of his cell-phone signal. Children with cell phones that include GPS

technology and location services can thus be located quickly. Concealed GPS devices can

assist with locating runaway teens. They also provide a more reliable service due to their

concealed nature. While a teenager aware of his cell phone's GPS device can turn the

service off, with a concealed location device, the teen is unaware the device is present.

Advantages:

Business management:

when a business issues mobile phones to its employees, it can use the tracking

information from the phones to see where its workers spend time while out on

the job. Phone-tracking services for businesses can also offer additional

features, like the ability to display a warning when an employee drives faster

than the legal speed limit; a feature that has proved of value to transportation

and delivery companies.

Emergency services:

By using information gathered from a phone’s GPS receiver and by working

with the phone provider to determine the device’s position relative to nearby

mobile mast, it is possible for the police force and fire and ambulance services



to be able to find lost and missing persons even when you don’t know where

you are or have been injured.

Colleague and friend tracking:

some mobile phones have tracking features that may enhance both your

business and social life. “Find My Friends” – a downloadable application for

the iPhone, is an example of such a service that displays on a map dots that

represent your friend’s or colleague’s location, allowing you to find each other

even in crowded places.

Child safety:

mobile phone-tracking makes it possible for parents to know where their

children are at all times. Some vendors sell phones with embedded software

that periodically sends data on the phone’s current location to a central server

via the mobile network. By logging in to the service online parents can view

their child’s current location and track where they have been previously. This

might be especially important if you can track that they have been to potentially

dangerous locations.

Disadvantages

Privacy concerns:

This is the principle drawback or disadvantage of mobile phone-tracking. It has

been argued that using geo-location information is an invasion of privacy.

Mobile phone companies have the ability to exploit the information and get an

extraordinary insight into the private lives of their mobile customers. But is

phone-tracking really an invasion of personal privacy? Well, every mobile user

has the ability to disable casual location-tracking applications like ‘Find my

Friends’ so that is not an issue: however, this tracking information remains

available to phone providers and emergency services.



CHAPTER 7

FUTURE WORK AND CONCLUSION

In the future its thought that as technology progresses so will the ability to track cell

phones, trace people and spy on people even more. The saying 'big brother is watching

you' has never been so true.

March 13, 2013 - Biometrics Research Group, Inc. expects that technologies that track

eye and gesture movements will play a large role in future mobile applications and

devices.

According to a recent New York Times report, the newest smartphone from

Samsung will have an eye-tracking feature that will allow its users to scroll down a page

without having to touch the screen.

The Future New Format:

The search engines and device manufacturers are testing a variety of new approaches to

mobile search, each of which has advantages and drawbacks for marketers when

compared to traditional search marketing strengths.

Voice search:

While this solution keeps the strength of real-time intent, the results the user receives

after her search are problematic. Many voice search tools simply deliver the user to a

mobile search results page

Proactive analysis:

Google Now uses your account data, location history, and past searches to predict

what you'd like to know - weather, traffic on your route home, good restaurants when

you're traveling - and then proactively provides this information. While these results

are well-targeted, their usefulness as marketing tools is more limited than traditional

search, as they remove the key expressed need (via a search query) and "moment of

truth" intent that makes search marketing so effective.

New secondary signals:

The new Moto X phone's "Moto Assist" feature is a great example of this approach,

which uses constantly tracked secondary signals to infer what the user is doing and

respond accordingly.


http://www.samsung.com/

http://bits.blogs.nytimes.com/2013/03/04/samsungs-new-smartphone-will-track-eyes-to-scroll-pages/

http://www.planetcreation.co.uk/sat-gps

http://www.planetcreation.co.uk/sat-gps


The classic format of typing a query and reviewing a SERP(Society For Elimination

Of Rural Poverty) is going to seem very quaint within the next few years. Smart

advertisers won't just build a mobile search strategy for today's formats - they'll pay close

attention to how their customers are searching and interacting with their mobile devices to

ensure they are present for every opportunity to respond to their customer's needs.

Conclusion:

Our proposal is advantageous in that the location of a mobile telephone can be accurately

tracked even in the multi-path fading and the NLOS environment, by using more accurate

tracking curves connecting the intersection points among circles with the radii being the

distances between corresponding BSs and the mobile telephone in a cellular mobile

communication system. We have described about accurate positioning of mobile

telephones, which can be used for several applications. The important considerations to

be undertaken while selecting a location based technology are location accuracy,

implementation cost, reliability, increasing functionality



REFERENCES

Sourabh Pawade, Pushkar Masodkar, Prof Pankaj Hedaoo/ International Journal

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micro-cells”, Proc. IEEE PIMRC, 1994.

G. Morley, and W. Grover, “Improved location estimation with pulse-ranging in

presence of shadowing and multi-path excess-delay effects”, Electronics Letters,

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Chin-Der Wann, Yi-Ming Chen, Position tracking and velocity estimation for

mobile positioning systems” Wireless Personal Multimedia Communications,

2002. The 5th International Symposium on Volume: 1 Digital Object

Identifier:10.1109/WPMC


http://www.ijera.com/

Final reportTracking And Positioning Of Mobile System In Telecommunication Networks

Engineering

positioning mobile positioning

mobile subscriber

positioning of mobile

mobile unit

mobile handset

mobile users

mobile telephone position

mobile telephone m1