This document discusses the use of a sniffer device to detect lost mobile phones. It begins with an introduction to cellular systems including mobile stations, base transceiver stations, base station controllers, and mobile switching centers. It then explains that a sniffer is a mobile base station with a directional antenna and tracking software that can detect lost phones by their IMEI number. The sniffer works by intercepting signals from lost phones and locating them through GPS. While useful for finding lost phones cost effectively, sniffers have privacy and security disadvantages.

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2. Out lines
 Introduction
 What is sniffer?
 Introduction of cellular systems
 Working of Sniffer
 Advantages and disadvantages of Sniffer.

3. Introduction
 Each and every day thousands of mobiles get misplaced or
lost.
 To prevent unauthorized person from making and receiving
the calls we use this technique.
 Effective way for the blocking of the lost mobile with the help
of International Mobile Equipment Identifier (IMEI).
 The device can be called as a mobile Base station that includes
Sniffer.

4. What is Sniffer ?
 The main scope is to detect the lost mobiles.
 For the detection of lost mobile SNIFFER plays a vital
role.
 The Sniffer is basically a transceiver that works in the
different frequency that we are commonly used.
 The sniffer device has to be designed for easy mobility
for the purpose of detection.

5. Introduction of Cellular systems

6. Mobile Station (MS):-
The Mobile Station (MS) is made up of two components:
1.Mobile Equipment (ME): Each phone is uniquely identified by
the International Mobile Equipment Identity (IMEI) number. This
number is burned into the phone by the manufacturer.
2.Subscriber Identity Module (SIM): The SIM is a small smart card
that is inserted into the phone and carries information specific to the
subscriber.
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7. Base Transceiver Station (BTS):-
 The BTS is the Mobile Station's access point to the network.
 It is responsible for carrying out radio communications between
the network and the MS.
 One BTS usually covers a single 120 degree sector of an area.
Base Station Controller (BSC):-
 BSC controls multiple BTSs.
 It handles allocation of radio channels, frequency from the
MS, and handovers from one BTS to another.
 It reduces the number of connections and allows for higher
capacity connections to the MSC.

8. Mobile Switching Center (MSC)
 The MSC is the heart of the GSM network.
 It handles call routing, call setup, and basic switching
functions.
 An MSC handles multiple BSCs as well as coordinates with
other MSC‘s.

9. IMEI
 International Mobile Equipment Identity.
 15 digit unique code that is used to identify the GSM
phone.
 When a phone is switched on, this unique IMEI
number is transmitted and checked against a data
base of black listed phones in the network’s EIR .
 To know the IMEI number the *#06# has to be pressed.

10. DESIGNING FOR THE SNIFFER
 The sniffer device can be called as a mobile base
station that includes the following important
components:-
1. Sniffer base station.
2. Unidirectional antenna.
3. Tracking software.

11. SNIFFER BASE STATION
 The sniffer is a small base station, it includes
transceiver section.
 It should operate at a frequency that is much different
from the frequency of the current cell in which the
operation of detection is being carried out.

12. UNIDIRECTIONAL ANTENNA
 The directional antenna acts as the eyes for the sniffer
for the purpose of the detecting the lost mobile phones.
 Antenna is a device which works at specified frequencies
range for transmitting or receiving the data signal.
 In general, antennas transmit power depending on lobe
pattern which varies from one antenna to the other.

13. SOFTWARE FOR THE TRACKING
 The software is used for the tracking of the lost mobile
phones.
 Main feature of this software is to create the data base and this
is mainly done using a Random Access Memory.
 The software has the input as the IMEI number of the lost
mobile phone from the RAM.
 After getting the input from the lost device that might respond
to the signal sent by the sniffer.

14. WORKING OF THE SNIFFER DEVICE
o If the connection of the lost mobile is Established with the
BTS, The MSC collects it’s IMEI number.
o If these number are matched with the reported lost no’s .
o It transferred the connection to the sniffer device.
o Searching can perform with the GPS system for more
accurate , fast detection and location can be tracked.

15. ADVANTAGES
 This method is used for finding the lost mobiles effectively.
 Cost effective.
 Low power consumption.
 Easy to design.

16. CONCLUSION
 In today’s life Mobile phones are the mainly used device for
communication ,so large no. of complaints regarding the
mobile phone that lost are comes.
 This method appears to be complex but for large scale
detection the overall effective cost of the design down.
 There are certain boundary conditions like the power of
the mobile should be good enough etc.. but this method
can be improved by using modern technologies.

17. Thank you
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