The document discusses the development of a device called 'sniffer' designed for detecting lost mobile phones by utilizing the International Mobile Equipment Identifier (IMEI). This device operates as a mobile base station with components like a unidirectional antenna and tracking software, enabling it to locate misplaced devices effectively. While it shows promise in recovery, further software development is necessary to enhance the process and tackle various boundary conditions.

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Sniffer for Detecting Lost
Mobile

2. Contents
• Introduction
• What Sniffer is ?
• IMEI
• Design
• Working
• Advantages
• Conclusion
• References

3. Introduction
• Each and everyday thousands of mobile get misplaced or lost,
through effective way for the blocking of the lost mobile to prevent
unauthorized person from making and receiving the calls has been
done by the manufacturers of the mobile with the help of
International Mobile Equipment Identifier (IMEI) has been done but
however there has been no development or very little progress for
the detection of the misplaced mobile phone.
• 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 .

4. What Sniffer is ?
• The device include a mobile Base station that includes Sniffer Base
station, Unidirectional antenna , Tracking software.
• The sniffer is a small base station that includes transceiver section.
• It should operate at a frequency which is much different from the
frequency of the current cell in which the operation of detection is
being carried out.
• The directional antenna is an important device that is to be designed
and used as it plays a major role.

5. IMEI
International Mobile Equipment Identity
Unique number embedded in the mobile phone.
Used for blocking of call made by unauthorized person
Numbering system is a 15 digit unique code
Identify-GSM/DCS/PCM
Check EIR (Equipment ID Register)

6. Design
The sniffer device has to be designed precisely and size should be
reduced for easy mobility for the purpose of detection.
The device can be called as a mobile base station that includes the
following important components:
• Sniffer base station
• Unidirectional antenna
• Tracking software

7. Sniffer Base Station
Small base station
Include transceiver section
Operated at frequency (900mhz which is VHF range)
OSCILLATOR circuit-for frequency range
Cooling is Important that has to be provided to the circuit
Low power transmitter (help in nature)

8. Unidirectional Antenna
Act as a eyes for the sniffer
Antenna is a device works at specified frequency
Transmitting & receiving data signal
Transmit power
Used to show radiation pattern

9. Radio Pattern
The Unidirectional Antenna
Radio Pattern

10. Tracking software
Feature: help to create database using RAM
IMEA - embedded in a chip
RAM stores - IMEI no.
Act as a database

11. Tracking software
RAM
Signal Information
IMEI Number
I/P
Lost Mobile

12. Working of Sniffers
The Working of sniffers is of two phases
Before Sniffer increases the frequency
After Sniffer increases the frequency

13. Before Sniffer Increases the Frequency

14. Before Sniffer Increase the Frequency
• In this a base station is used that works as a middle point of mobile
phone and MSC (Mobile Switching centre).
• There is two way communication between devices. Before the
communication establishment, the authentication of SIM card (Using
IMEI) and handset (Using EIR) is done.
• The EIR is located at MSC and it contains the contains the IMEI of the
lost mobile.

15. After Sniffer Increases the Frequency
• The information from this communication is fed to sniffer device and
start to locate the mobile phone.
• The connection between BTS and device is lost due to EIR request.
• The lost device search the device to get locked and send the signal
which is received by sniffer device and connection between them is
established.
• Now IMEI of lost device is validated with stored IMEI and then
connection is established.

16. Contd..
• After that the location is traced. During this process, if another device
try to connect with sniffer then the connection is denied.
• This can’t be done with the GPS because the sniffer can only work
with frequency only used with operators.
• Now the antennas are used to track different positions of the lost
device.

17. After Sniffer Increases the Frequency

18. Advantages
• This method is used for finding the lost mobiles effectively
• Cost effective
• Low power consumption
• Easy to design

19. Conclusion
• “Sniffer for the detection of lost Mobile phones” paves a way by
means of which the lost mobile phones can be recovered. But the
process of detection is yet to be developed through the software.
• There are certain boundary conditions or criteria that have to be
qualified for the identification of the lost mobile like the power of the
mobile should be good enough , the mobile phone should not be in
the shadow region etc., but however this method can be improved by
using modern technologies and devices.

20. References
• Schiller , “Mobile Communication", Pearson Education 1 Edition, 7th
reprint-2003.
• John D Kraus, “Electromagnetics", MH,
• Jordan et al, “Electromagnetic waves and radiation system” , Prentice
Hall
• www.gsmworld.com
• http://ericsson.com
• http://iec.org