19-09-2012, 01:44 PM
STUDY OF CELLULAR PHONE DETECTION TECHNIQUES
[attachment=34061]
INTRODUCTION
Example of Need for Better Cellular Phone Detection Technology
Imagine you are an IT security consultant for pharmaceutical
companies.Recently a company hired you to find out why their latest drug leaked to one
of their competitors prior to release. The company has many labs, each with sensitive
drug information stored on computers that are closely monitored by cameras. The
building they are housed in has security guards at every entrance and every employee is
required to wear ID. Visitors must be escorted to ensure that no drug information leaks
out.
You meet with the head of security and go over the security procedures. After a
little digging you find that employee-owned electronic devices such as cellular phones
are allowed in and out of the facility. The company feels that the non-disclosure
agreements in combination with security personnel monitoring everything on camera are
strong enough to keep employees honest and that the cost of screening for electronic
devices is too high. You tell the head of security that tomorrow morning security must
seize every employee's electronic device as they enter the building.
Cellular Phone Technology
Cellular phonetechnology is rapidly changing. Features like Bluetooth, USB,
high resolution cameras, microphones, Internet, 802.11 wireless, and memory cards are
added every year.Also, the communication technology a cellular phone uses such as
CDMA, GSM, 3G, and 4G are rapidly changing.
Cellular Phone Features
Bluetooth is a secure wireless protocol that operates at 2.4 GHz. The protocol
uses a master slave structure and is very similar to having a wireless USB port on your
cellular phone. Devices like a printer, keyboard, mouse, audio device, and storage
device can be connected wirelessly.This feature is mainly used for hands-free devices
but can also be used for file transfer of pictures, music, and other data.
Universal serial bus (USB) is a way for cellular phones to connect to a computer
for data transfer. This feature is very similar to Bluetooth for a cellular phone with the
exception of using a cable. On today's cellular phones this feature is mainly used for
charging the battery or programming by the manufacturer. It can also be used to transfer
pictures, music, and other data.
Cameras on cellular phones are a very popular feature that was added in the last
10 years. In recent years, high resolution cameras have become a standard feature.
Most cellular phones will come with at least a 2 mega pixel camera and the more
expensive phones can be as much as 8 mega pixels.
Cellular Phone Communication Standards
Currently the three main technologies used by cellular phone providers are 2G,
3G, and 4G. Each generation of technology uses a different transmission protocol. The
transmission protocols dictate how a cellular phone communicates with the tower. Some
examples are: frequency division multiple access (FDMA), time division multiple access
(TDMA), code division multiple access (CDMA), global system for mobile
communications (GSM) , CDMA2000, wideband code division multiple access
(WCDMA), and time-division synchronous code-division multiple access (TD-SCDMA).
All of these protocols typically operate in the 824 - 894 MHz band in the United States.
Some protocols, such as GSM (depending on the provider)will use the 1800 - 2000 MHz
band [6].
Cellular Phone Detectors Available Today
To get a good grasp on what is available todaylet’s take a close look at some off
the shelf cellular phone detectors. Most detectors are manufactured with the intent that
the cellular phone is stationary and powered on. They generally have the same features
and it is questionable whether or not they actually detect a cellular phone.
The two most popular cellular phone detectors available on the market today are
produced by Berkeley Varitronics Systems and Mobile Security Products. These
companies produce the wolfhound cell phonedetector and Cellbuster respectively.
Detecting and Locating Cell Phones in Correctional Facilities
This article details the growing problem with cellular phones in correctional
facilities and lays out the constraints used to develop their solution. According to the
research, cellular phones in a correctional facility are used to operate criminal
enterprises, threaten witnesses, harass victims, plan uprisings, and undermine security.
Their problem is monitoring, controlling, and locating cellular phones in a correctional
facility [4].
EVI's possible solutions include physical search, non-linear junction detectors,
signal jamming, shielding, network provider location based screening, RF detection, and
their custom proprietary solution. They rule out all solutions but their own custom
solution that uses a system of networked sensors that are controlled by a central
computer. EVI uses proprietary software that determines the cell phone's location and
detects any RF emissions. The location of detected cellular devices is displayed on a
facility map [4].
Design Description
Using a down converter, voltage controlled oscillator (VCO), and a bandpass
filter is the second technique explored for cellular phone detection. Two signals are
inputted into the down converter. The first signal is from the antenna and is between 829
- 835 MHz depending on the cellular phone (832 MHz for this expierment). The other
signal is from the VCO, which is tuned to 800 MHz. The down converter multiplies the
two signals together producing the sum and the difference. This is then filtered by a
bandpass filter with the passband lower and upper edges respectively at 28 MHz and 36
MHz.Filtering eliminates the sum of the signals and any environmental noise. Now all
that remains is the difference, a 29 - 35 MHz signal that indicates an active cellular phone
is in the area. This can easily be converted using analog to digital converters and output
to an alarm or computer.
[attachment=34061]
INTRODUCTION
Example of Need for Better Cellular Phone Detection Technology
Imagine you are an IT security consultant for pharmaceutical
companies.Recently a company hired you to find out why their latest drug leaked to one
of their competitors prior to release. The company has many labs, each with sensitive
drug information stored on computers that are closely monitored by cameras. The
building they are housed in has security guards at every entrance and every employee is
required to wear ID. Visitors must be escorted to ensure that no drug information leaks
out.
You meet with the head of security and go over the security procedures. After a
little digging you find that employee-owned electronic devices such as cellular phones
are allowed in and out of the facility. The company feels that the non-disclosure
agreements in combination with security personnel monitoring everything on camera are
strong enough to keep employees honest and that the cost of screening for electronic
devices is too high. You tell the head of security that tomorrow morning security must
seize every employee's electronic device as they enter the building.
Cellular Phone Technology
Cellular phonetechnology is rapidly changing. Features like Bluetooth, USB,
high resolution cameras, microphones, Internet, 802.11 wireless, and memory cards are
added every year.Also, the communication technology a cellular phone uses such as
CDMA, GSM, 3G, and 4G are rapidly changing.
Cellular Phone Features
Bluetooth is a secure wireless protocol that operates at 2.4 GHz. The protocol
uses a master slave structure and is very similar to having a wireless USB port on your
cellular phone. Devices like a printer, keyboard, mouse, audio device, and storage
device can be connected wirelessly.This feature is mainly used for hands-free devices
but can also be used for file transfer of pictures, music, and other data.
Universal serial bus (USB) is a way for cellular phones to connect to a computer
for data transfer. This feature is very similar to Bluetooth for a cellular phone with the
exception of using a cable. On today's cellular phones this feature is mainly used for
charging the battery or programming by the manufacturer. It can also be used to transfer
pictures, music, and other data.
Cameras on cellular phones are a very popular feature that was added in the last
10 years. In recent years, high resolution cameras have become a standard feature.
Most cellular phones will come with at least a 2 mega pixel camera and the more
expensive phones can be as much as 8 mega pixels.
Cellular Phone Communication Standards
Currently the three main technologies used by cellular phone providers are 2G,
3G, and 4G. Each generation of technology uses a different transmission protocol. The
transmission protocols dictate how a cellular phone communicates with the tower. Some
examples are: frequency division multiple access (FDMA), time division multiple access
(TDMA), code division multiple access (CDMA), global system for mobile
communications (GSM) , CDMA2000, wideband code division multiple access
(WCDMA), and time-division synchronous code-division multiple access (TD-SCDMA).
All of these protocols typically operate in the 824 - 894 MHz band in the United States.
Some protocols, such as GSM (depending on the provider)will use the 1800 - 2000 MHz
band [6].
Cellular Phone Detectors Available Today
To get a good grasp on what is available todaylet’s take a close look at some off
the shelf cellular phone detectors. Most detectors are manufactured with the intent that
the cellular phone is stationary and powered on. They generally have the same features
and it is questionable whether or not they actually detect a cellular phone.
The two most popular cellular phone detectors available on the market today are
produced by Berkeley Varitronics Systems and Mobile Security Products. These
companies produce the wolfhound cell phonedetector and Cellbuster respectively.
Detecting and Locating Cell Phones in Correctional Facilities
This article details the growing problem with cellular phones in correctional
facilities and lays out the constraints used to develop their solution. According to the
research, cellular phones in a correctional facility are used to operate criminal
enterprises, threaten witnesses, harass victims, plan uprisings, and undermine security.
Their problem is monitoring, controlling, and locating cellular phones in a correctional
facility [4].
EVI's possible solutions include physical search, non-linear junction detectors,
signal jamming, shielding, network provider location based screening, RF detection, and
their custom proprietary solution. They rule out all solutions but their own custom
solution that uses a system of networked sensors that are controlled by a central
computer. EVI uses proprietary software that determines the cell phone's location and
detects any RF emissions. The location of detected cellular devices is displayed on a
facility map [4].
Design Description
Using a down converter, voltage controlled oscillator (VCO), and a bandpass
filter is the second technique explored for cellular phone detection. Two signals are
inputted into the down converter. The first signal is from the antenna and is between 829
- 835 MHz depending on the cellular phone (832 MHz for this expierment). The other
signal is from the VCO, which is tuned to 800 MHz. The down converter multiplies the
two signals together producing the sum and the difference. This is then filtered by a
bandpass filter with the passband lower and upper edges respectively at 28 MHz and 36
MHz.Filtering eliminates the sum of the signals and any environmental noise. Now all
that remains is the difference, a 29 - 35 MHz signal that indicates an active cellular phone
is in the area. This can easily be converted using analog to digital converters and output
to an alarm or computer.