SNIFFERfor Detection of Lost Mobile Phones

Presented ByRAJASHREE PRAHARAJ, 1011016262 ECE-E

What Happens when you lose your Mobile Phone?

Reporting…Searching

…Praying…

CONTENTS• What is a sniffer ?• What is IMEI?• Designing of the sniffer

Sniffer base station Unidirectional Antenna Tracking software

• Working of sniffer device• Advantages• Limitations• References

What is a Sniffer?

• The sniffer is basically a transceiver that works in the frequency which is in the special unused range that is operated by the service provider or at a frequency that is much different than the one that is being used.

• For the detection of lost mobile SNIFFER plays a vital role .

• The sniffer device has to be designed precisely and size should be reduced for easy mobility for the purpose of detection .

What is IMEI?(International Mobile Equipment

Identifier)

What is IMEI?I n t e r n a ti o n a l M o b i l e E q u i p m e n t I d e n ti fi e r

• Each mobile device has a globally unique IMEI

• Used for blocking of call made by unauthorized person once the mobile is reported as stolen

• 15 digit unique code

• identify-GSM/DCS/PCS phone

• IMEI number is transmitted and checked against a data base of black listed or grey listed phones in the network’s EIR (Equipment ID Register), if match found then the network can perform different actions.

Gray ListAllow the Phone to be used, but can be tracked to see who has it.

Black ListListing the phone from being used on any number where there is an EIR match

What Sniffer actually has?

Designing of the Sniffer

The sniffer device can be called as a mobile base station

that includes the following important components:

• Sniffer base station

• Unidirectional antenna

• Tracking software

Small Base Station

• Facilitates wireless communication between the user equipment and the network• Sniffer is a small base station which includes transceiver section.

• It operate at a frequency that is much different from the frequency of the current cell

• Frequency generated by transceiver is around 900MHz(VHF)

• Hence a proper cooling of the oscillator circuit, generating the high frequency, has to be ensured.

Unidirectional Antenna

(Unidirectional Antenna Radiation Pattern)

• Antenna is a device which works at specified frequency range for transmitting or receiving the data signal.

•Acts as the eyes of the sniffer for the purpose of the detection.

• Transmission power depends on lobe pattern which varies from one antenna to the other.

• The power radiated by the antenna should be properly designed in order to avoid interference with the near by cells.

• Effective gain has to be taken into account as this shows the ability of the antenna to capture the signal that the lost mobile is transmitting.

Design Parameters of Antenna• The shape of the radiation system is independent of R, as long R is chosen to be sufficiently large and much greater than the wavelength.

• other factors : gain and directivity

• Gain [G( )]= ratio of the antenna radiated power density at a distant point to the total antenna input power (Pin).

• Directivity [D( )]= the ratio of the antenna radiated power density at a distant point to the total antenna radiated power (Prad) radiated isotropically.

,

,

Design Parameters of Antenna• Another factor: radiated power intensity U and total radiated power Prad satisfy the below relationship;

Prad =

• The average power that gets radiated is given as:

Pavg = Prad/4π (watts per steradian)

•Total incident power is: Pin = Prad+Pl

• The power gain of the antenna is given as: gp = 4πU/Pin

• The ratio of gain power to the directive gain is referred as a measure of efficiency of the antenna: gp/gd = Prad/(Prad+Pl)

2

0 0

sinU d d

Contd..• effective area = aperture or capture area that is exposed to the em waves and is related to the directive gain of the antenna through the relation; Aeff = gdλ2/4

• Effective area and gain vary directly for a given frequency and efficiency .

• Unidirectional antenna = high gain and high directivity (for long distance communication and better signal quality)

• Orientation of the antenna = fixed in one particular direction

Software for Tracking

• Software helps in the process of creation of the data base and this is mainly done using a Random Access Memory(RAM).

• Lost IMEI number is embedded in the chip.

• It has the input as the IMEI number of the lost mobile phone from the RAM using the SQL query.

• Programming is done with C or Java, but C is most preferred as it is easily embedded within the chips.

Working of the Sniffer

The entire working of the sniffer is categorized

in two phases :

• Before Sniffer increases the frequency

•After Sniffer increases the frequency

Before Sniffer Increase The Frequency

After Sniffer Increase The Frequency

Fig: The lost mobile phone connection establishes a connection with the sniffer

Sniffer tries to communicate with the lost mobile phone

Fig: Sniffer trying to communicate with the lost mobile phones.

Advantages

• Useful in detection of lost mobile on a large scale

• Overall effective cost of the design and the detection is low

• Low power consumption

Limitations

Certain boundaries :

• Power of the mobile should be good enough• Mobile should not been in shadow region

Note: “Method can been improved by using modern technology and devices”

References•Schiller, “Mobile Communication”, Pearson Education 1 Edition, 7th reprint -2003.

•R. S. Satya Sri Ambica, P. Padma Priya, Dr.N.Srinivasu, “Sniffer Technology to Detect Lost Mobile ”, International Journal of Engineering Trends & Technology, volume 4,issue4 –April 2013.

• Puthiyavan,U., “Enhancing User Privacy- Location Based Search Using MEMD” , IEEE International Conference on Portable Information Devices 2007, May 2007, Pp-1-5.

Thank You