Transcript Document 7425788

Cell Phone and Cellular
Networks
Laurie Shteir, CIS Department
The Basics
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Sending a call
• Sound is converted into radio waves
• Travel thru the air until they reach a base station
• Base station sends your call thru the telephone network
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Receiving a call
• Message travels thru the Telephone Network until it
reaches a base station close to your wireless phone
• Base station sends out radio waves detected by a
receiver in your telephone
• Telephone converts the signals into voice
Video on cell towers
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Communications, Information and Entertainment
Device
Important technology device world wide
• 80% of the world’s pop has coverage
• Largest growth rate – Africa
• Tremendous growth due to Pre-paid service
with no commitment to a long term contract
• Developing countries have poor wire – line
infrastructure, cost of computers, poor quality
of lines, lack of consistent electricity in areas
Cell Phone Users in
Africa
1998
2 Milliion
2002
28 Million
2003
51 Million
2004
82 Million
International
Telecommunication Union
(ITU), The Economist
Entrepreneur Opportunities in Developing Countries
• Selling phone services to villages on a per use basis.
• Sellers of prepaid phone cards including poor urban
youths and small business owners.
• Users of phones who gain business and employment
opportunities mentioned above.
Challenges/Solutions
Challenges
• Cost of the handsets
• Coverage is concentrated in cites and specific
countries
• Poverty
• Governmental restrictions on information
Solutions
• Motorola won a contract to supply 6 million handsets
to African nations at a cost of $40/handset
• Business/Governments working together
• Recycled Phones
Cellular Communications
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3G Cellular Technology(144 Kbps to 2.4 Mbps)
• Wireless Broadband
• Browse the Web, watch video or TV, play games
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PCS (Personal Communications Services)
• Term used by US FCC – all wireless digital communications
• Cellular telephones, PDAs, pages, fax machines
• Services on these devices: Voice Mail, Call forwarding, faxing, caller ID,
Email and Internet access
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Manufacturers of Cell Phones include
• Nokia (31% Q1 of 2007global market),Audiovox(UT Starcom, Motorola,
Benefon,……
Choices:
• Carrier (Verizon, T-Mobile, Cingular/AT&T, Sprint/Nextel)
Plan, phone, features and services
Technology
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2-way radio between mobile phones and base stations
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Geographical area split into overlapping areas called cells
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Typically 10 square miles
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Antennas are on a tower not at ground level – restrict exposure to electromagnetic fields
Base station communicates with mobile phones thru a channel
Channel has 2 frequencies: transmitting data and receiving data
MTSO (Mobile Telephone Switching Office)
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Each cell has a base station (tower and building containing equipment)
Tower includes antennas, amplifiers, transceivers/transmitters
Handles phone connections to land lines
Controls the base stations
Hand offs calls from one cell to another
Keeps track of the cell you are located in
Cell phone codes
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Identify the phone, phones owner and the service provider
ESN (Electronic Serial Number) programmed into the phone when manufactured,
permanent code
MIN (Mobile Identification Number) - a 10-digit number derived from your phone's
number , programmed in when you activate the phone
SID (System Identification Code), unique number assigned to each carrier
Powering UP/Making a Call
Powering Up
Power is turned on, phone registers a unique identifier System
Identification Code (SID) - to the Mobile Switching Office thru
a control channel (special frequency used to communicate)
Phone transmits a registration request which the MTSO keeps
track of to identify the cell you are in when it wants to ring the
phone
MTSO decides on a frequency to use for your call
Making a call
Cell phone identifies the closest base station, determines the
strongest channel, phone transmits: MIN (your cell phone number)
its ESN, and the number you are dialing
Cell service verifies you are a legitimate customer and sends a
channel assignment
Cell phone tunes to the channel and begins the call
Call is connected (you are talking on a 2-way radio)
As you travel the signal is moved from cell to cell
Technology
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Roaming
• Leaving an area covered by your service
provider
• MTOS offices communicate with each
other to track your calls
Cellular Technologies
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GSM: most popular worldwide
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Europe, Asia, Africa
Better International Service
Dominate the world market
Only on Digital Networks
5 hours of talk time on a a battery charge
GSM Phone SIM card
Cingular, T-Mobile
CDMA: most prevalent in US and
competes equally with GSM
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In US legislation does not require a specific
standard
Better US coverage
Used in US, Canada, Australia and some
south eastern countries
3 hours of talk time on a battery charge
Common Platform for 3G Services
Allows more subscribes to be connected at
the same time
Slight edge in quality of service
Sprint PCS, Verizon and Virgin Mobile.
Can I take my US Phone to Europe and
make calls?
Only if you have a Triband Phone or a Quad
Band Phone (world phone)
Motorola
Sony
Nokia
Samsung
Service Plans
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“Pay as you go”
Whenever, or anytime, minutes
Weeknight minutes
Weekend minutes
Rollover minutes
“In calling” for free
Need to learn about hidden usage fees
• Additional minutes, roaming fees
Health Concerns
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Problems with cell phones
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Non repairable corrosion of parts
Inability to provide 100% service
Interference
Extreme Heat – damage battery of components of cell phone
Health Concerns
 Support needed research into possible biological effects of
RF (radio frequency)of the type emitted by wireless phones
 Design wireless phones in a way that minimizes any RF
exposure to the user that is not necessary for device
function; and
 Cooperate in providing users of wireless phones with the
best possible information on possible effects of wireless
phone use on human health
 FCC operates a website to determine the SAR value of cell
phones
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http://www.fcc.gov/cgb/sar/
Suggestions for Securing a Cell
Phone
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Don’t store sensitive information
Don’t trust the cell phone company to keep your data secure
Check Billing for Fraud, Cell phone signals can be intercepted and cloned,
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“tumbling” (one bogus call here and there)
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Ask for confirmation in writing that device has been disabled
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Kill your battery
Make costly calls
Send text messages
Assign passwords when possible, cell phones are small and easy to loose
Report loss immediately to your provider
Don’t be fooled by cell phone insurance: only covers the device, not
charges for calls
Careful if you recycle your old phone
Turn off Bluetooth signal to non-discoverable
Viruses for cell phones infancy stage, hidden in applications for cell phones
Better Business Bureau reports: cell phone providers are the number 1 complaint
among consumers
Ethical Considerations
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Cell Journalism
Authenticity of pictures
Having pictures taken, video and voice recorded without permission
Classroom use
• Highschool and College
Location Information
3G phones with integrated GPS
E-911 standard from the FCC
sensor networks able to determine locations within buildings.
Slippery-Slope, Privacy, Ethics
Security
• Generally non-secure
• Cell Phone Voice Mail is easily hacked by certain provider
Spoofing caller ID
Disposable Phones ( A Phone You can Loose)
• Very little audit trail – no way to track the specific owner
• Used by folks with bad credit, emergency phone, vacationing traveler,
mechanism for limiting use
• Law Enforcement Officials: Also used by Terrorists and Criminals
• No contract, no credit check, no long term obligation
• Difficult or impossible to track
• Law Enforcement Officials – Disposable phones were used to detonate
the bombs terrorists used in the Madrid train attacks in March 2004.