Transcript WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS

The Wireless
Revolution
Digital Revolution –
Device, Networking and Communication Trends
What Invention Started Digital Revolution?
• Digital Convergence:
• Gradual merger of computing and communications
• Telephone networks and computer networks converging into
single digital network using Internet standards
• Broadband Wired:
• More than 74 percent U.S. Internet users have broadband
access
• Broadband Wireless:
• Voice, data communication are increasingly taking place over
broadband wireless platforms
The Wireless Revolution
• Mobile phones have become mobile platforms for
delivering digital data, used for recording and
downloading photos, video and music, Internet
access, and transmitting payments.
• An array of technologies provides high-speed
wireless access to the Internet for PCs and other
wireless handheld devices and cell phones.
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Two of every five U.S.
households have only
wireless phones.
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Smartphone & Cellphone
Feature phone
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Why Wireless
• Businesses increasingly use wireless to
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cut costs (labor)
increase mobility and flexibility
better access to information
easier network expansion
create new products and services
enhanced guest access
Wired Network
• A wired network uses cables to connect network
devices
• Wired networks using Ethernet or coaxial cables or
fiber optic cables are fast, secure, and simple to
configure
• Devices tethered to cables have limited mobility
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Wireless Networking
 A network is considered wireless when data is
transmitted from one device to another without
cables or wires
 Tend to be slower than wired networks
 Have more security issues
 Common wireless terms:
› Wi-Fi - common standard technology for building home
networks and other LANs
› Hotspots – many businesses use Wi-Fi technology to allow
the public an access point to a wireless network
› Bluetooth – allows handhelds, cell phones, and other
peripherals to communicate over short ranges
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Wired vs. Wireless
• Wired:
• More about
performance and
security
• Great long-haul
technology
• Power management is
less important
• Point-to-point nature
• Wireless:
• More about mobility
and freedom
• Good access
technology
• Power management is
important
• Broadcast nature
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Wireless Characteristics
• Communication without wires
• Wires are replaced by electromagnetic waves, which
carry a signal through atmospheric space
• use radio frequency RF waves, which ranges from
3 kHz to 300 GHz
• or infrared IR, which ranges from 3 THz to 430 THz
Frequency is measured in Hertz
(where one cycle per second = 1 Hertz)
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Electromagnetic Spectrum
Wavelength & Frequency
Speed of light v = λ f
(Higher Energy)
(Lower Energy)
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Electromagnetic Spectrum
• Electromagnetic spectrum of radiation is
the basis of all telecommunications signals,
wired (through some kind of media) and
wireless (through air or vacuum)
• Radio-frequency (RF) spectrum is the
part of the electromagnetic spectrum
that carries most communications
signals
electromagnetic spectrum
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Electromagnetic Spectrum
Showing Radio Frequency
lower energy
higher energy
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Electromagnetic Spectrum
Showing Radio Frequency
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Electromagnetic Spectrum
Showing Radio Frequency
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Electromagnetic Spectrum
Showing Radio Frequency
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Electromagnetic Spectrum
Showing Radio Frequency
Microwave
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Wireless Communications Media
• Five Types of Wireless Communications Media
• Infrared Transmission
• Sends signals using infrared light
• Frequencies are too low to see (1-16 megabits per
second)
• Broadcast Radio
• AM/FM, CB, ham, cellphones, police radio
• Sends data over long distances using a transmitter and a
receiver (up to 2 megabits per second)
• Cellular Radio
• Form of broadcast radio
• Widely used in cellphones and wireless modems
• Transmits voice and digital messages
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• Five Types of Wireless Communications Media
(continued)
• Microwave Radio
• Superhigh-frequency radio transmit voice and data at 45
megabits per second
• Requires line-of-sight transmitters and receivers to transfer
data from tower to tower.
• More than ½ of today’s telephones systems use
microwave
• Communications Satellites (Satellite Radio)
• Microwave relay stations in orbit around the earth
• Basis for Global Positioning Systems (GPS)
(continued)
• Cover broad service area
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Management Information Systems
Lecture 9 The Wireless Revolution
THE WIRELESS COMPUTING LANDSCAPE
Frequency Ranges for Communications Media and
Devices
Radio Waves
• Radio waves carry music, conversations,
pictures, and data invisibly through the air over
millions of miles.
• Radios can transmit and/or receive radio
waves.
Wireless Signal_BBC
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Propagation of Radio Waves
• Radio waves (shortened to RF for Radio
Frequency) propagate in a straight line in
several directions at once. In a vacuum,
radio waves propagate at 3.108 m/s.
• In any other medium, the signal gets weaker
due to
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Reflection
Refraction
Diffraction
Absorption
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Radio Waves
Signals received even though transmitters are not in the line of sight.
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They’re Everywhere
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They’re Everywhere
• Some examples:
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AM/FM Radios
Cell Phones
GPS Receivers
Wi-Fi
GPS
RFID
• Some other
examples:
• Cordless Phones
• Garage Door Openers
• Radio-Controlled Toys
• Television Broadcasts
• Ham Radio
• Etc.
• ZigBee (IoT, low cost, low power)
• UWB (Ultra-wideband)
• NFC (Near Field Communication)
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Some other (not-so-obvious) examples
• Radar (police, air traffic control, military
applications)
• Microwave ovens
• Navigation systems
• Airplanes (contain dozen different radio
systems)
• Baby monitors
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Radio Basics
• Any radio setup has two parts: Transmitter and
Receiver
• Transmitter takes some form of message (someone’s
voice, pictures for TV set, etc.) encodes it into a sine
wave and transmits it with radio waves.
• Combination of encoded message on a radio
wave is commonly referred to as a signal.
• Receiver receives radio waves and decodes
messages from the sine waves.
• Both transmitter and receiver use antennas to
radiate and capture radio waves.
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Transmitter & Receiver
Radio_BrainPop
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Transmitter & Receiver Description
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Transmitter Description
Radio
Transmitter
Combine
Information
(voice message)
Radio Waves
Antenna
Carrier
Wave
Transmitter generates its own sine wave using oscillators.
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Receiver Description
Radio
Receiver
Antenna Separate
Carrier
Wave
Information
(voice message)
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Communication Satellites
• Can be placed at different heights: GEO, MEO, LEO
• GEO – geostationary earth orbit
• 22,300 miles above earth; travel at the same speed
as the earth and so appear to us to be stationary
• Always above equator, mostly for broadcast
communications and weather satellites
• Transmission delay can make conversations difficult
• MEO – medium-earth orbit
• 5,000 – 10,000 miles up
• GPS satellites
• LEO – low-earth orbit
• 200 – 1,000 miles up
• Has no signal delay, International Space Station
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Communication Satellites
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GPS: What is It?
• A simplistic explanation: GPS uses these “manmade stars” as reference points to calculate
positions accurate to a matter of meters.
• Uses the principle of
triangulation and time-of-arrival of signals to
determine the location of a GPS receiver.
• Global positioning System
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GPS: What is It?
• Long-Distance Wireless: One-Way Communication
• 24 to 32 MEO satellites in 6 orbital planes
continuously transmitting timed radio signals
• Each satellite circles earth twice each day at
11,000 miles up
• GPS receivers pick up transmissions from up to 4
satellites and pinpoint the receiver’s location
• Accurate within 3 – 50 feet, with a norm of 10 feet
accuracy
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GPS_BrainPop
GPS_NASA
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GPS: What is It?
• Each of these 3,000- to 4,000-pound solarpowered satellites circles the globe at about
12,000 miles (19,300 km), making two complete
rotations every day.
• The orbits are arranged so that at any time,
anywhere on Earth, there are at least four
satellites "visible" in the sky.
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Triangulation
• A GPS receiver's job is to locate four or more of
these satellites, figure out the distance to each,
and use this information to deduce its own
location.
• This operation is based on a simple
mathematical principle called triangulation or
trilateration.
• Triangulation in three-dimensional space can
be a little tricky, so we'll start with an
explanation of simple two-dimensional
trilateration.
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An example of 2D triangulation
• Imagine you are somewhere in the United
States and you are TOTALLY lost -- for whatever
reason, you have absolutely no clue where you
are.
• You find a friendly local and ask, "Where am I?"
He says, "You are 625 miles from Boise, Idaho."
• This is a nice, hard fact, but it is not particularly
useful by itself. You could be anywhere on a
circle around Boise that has a radius of 625
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miles
Where in the U.S. Am I?
• To pinpoint your location better, you ask
somebody else where you are.
• She says, "You are 690 miles from Minneapolis,
Minnesota.“ If you combine this information with
the Boise information, you have two circles that
intersect.
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Where in the U.S. Am I?
• If a third person tells you that you are 615 miles
from Tucson, Arizona, you can eliminate one of
the possibilities, because the third circle will only
intersect with one of these points. You now know
exactly where you are…
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Where in the U.S. Am I?
• You are in Denver, CO!
• This same concept works in three-dimensional
space, as well, but you're dealing with spheres
instead of circles.
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3D Triangulation
• Fundamentally, three-dimensional trilateration is
not much different from two-dimensional
trilateration, but it's a little trickier to visualize.
• Imagine the radii from the examples in the last
section going off in all directions. So instead of a
series of circles, you get a series of spheres.
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GPS Triangulation
• If you know you are 10 miles from satellite A in
the sky, you could be anywhere on the surface
of a huge, imaginary sphere with a 10-mile
radius.
10 miles
Earth
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GPS Triangulation
• If you also know you are 15 miles from satellite B,
you can overlap the first sphere with another,
larger sphere. The spheres intersect in a perfect
circle.
15 miles
10 miles
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GPS Triangulation
• The circle intersection implies that the GPS receiver
lies somewhere in a partial ring on the earth.
Perfect circle formed from
locating two satellites
Possible
Locations of
GPS Receiver
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GPS Triangulation
• If you know the distance to a third satellite, you
get a third sphere, which intersects with this
circle at two points.
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GPS Triangulation
• The Earth itself can act as a fourth sphere -- only
one of the two possible points will actually be
on the surface of the planet, so you can
eliminate the one in space.
• Receivers generally look to four or more
satellites, however, to improve accuracy and
provide precise altitude information.
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Typical GPS Applications
• Location - determining a basic position
• Navigation - getting from one location to
another
• Tracking - monitoring the movement of people
and things.
• Mapping - creating maps of the world
• Timing - bringing precise timing to the world
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GPS Trilateration
GPS-How GPS Works-Trilateration
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Management Information Systems
Lecture 9 The Wireless Revolution
THE WIRELESS COMPUTING LANDSCAPE
Cellular Network Standards and Generations
Standards:
• Global System for Mobile Communication (GSM)
• Code Division Multiple Access (CDMA)
How Do Cell Phones Work
Cell Phone_BrainPop
Cellular Principles
• Frequency reuse – same frequency in
many cell sites
• Cellular expansion – easy to add new cells
• Handover – moving between cells
• Roaming between networks
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Frequency Reuse
• Adjacent cells assigned different frequencies to avoid interference or
crosstalk
• Objective is to reuse frequency in nearby cells
• 10 to 50 frequencies assigned to each cell
• Transmission power controlled to limit power at that frequency escaping to adjacent cells
• The issue is to determine how many cells must intervene between two cells using the
same frequency
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Cellular Network Organization
• Use multiple low-power transmitters (100 W or less)
• Areas divided into cells
• Each served by its own antenna
• Served by base station consisting of transmitter, receiver, and
control unit
• Band of frequencies allocated
• Cells set up such that antennas of all neighbors are equidistant
(hexagonal pattern)
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Cell of Cellular Network
segmentation of the area into cells
possible radio coverage of the cell
cell
idealized shape of the cell
• Use of several carrier frequencies
• Not the same frequency in adjoining cells
• Cell sizes vary from some 100 m up to 35 km depending on
user density, geography, transceiver power etc.
• Hexagonal shape of cells is idealized (cells overlap, shapes
depend on geography)
• If a mobile user changes cells, handover of the
connection to the neighbor cell
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Cellphone Connection Stages
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Cell Phone Towers
• A cell-phone tower is typically a steel pole or
lattice structure that rises hundreds of feet into
the air.
• This tower is used by three
different cell-phone providers.
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1G
• Developed in 1980s & completed in
early 1990s
• Based on analog system for voice
• Speed up to 2.4 kbps
• AMPS (Advance Mobile Phone System) was
launched by the US & it was the 1G mobile system
• Allows user to make voice calls in 1 country
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2G
• Developed in late 1980s & completed in
late 1990s
• Based on digital system
• Speed up to 64 kbps
• Services such are digital voice & SMS with more
clarity
• Semi global facility
• Can use TDMA (Time Division Multiple Access) or
CDMA (Code Division Multiple Access) for
increasing capacity
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2.5G
• 2.5 G – packet-switching
• Connection to the internet is paid by
packets and not by connection time.
• Connection to internet is cheaper and faster
The service name is GPRS – General Packet
Radio Services
• Enhanced Data rates for GSM Evolution
(EDGE): 2.75G
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3G
• Developed between late 1990s & early
until present day
• Transmission speed from 125 kbps to
14 Mbps
• Superior voice quality
• Supports video and other rich media
• Always-on transmission for e-maill,
• Web browsing, instant messaging,
• On-line shopping/ banking, games, etc.
• Global roaming
2000s
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4G
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Developed in 2010
Faster & more reliable
All-IP based technology
Speed up to 100 Mbps
High performance
Easy roaming
Low cost
LTE (Long Term Evolution)
• Promises data transfer rates of 100 Mbps
• Based on UMTS 3G technology
• Optimized for All-IP traffic
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5G
• Next major phase of mobile
telecommunication & wireless
system
• 10 times more capacity than
others
• Expected speed up to 1Gbps
• More faster & reliable than 4G
• Lower cost than previous
generations
• Commercially available by around
2020
© 2006 by Prentice Hall
Management Information Systems
Lecture 9 The Wireless Revolution
THE WIRELESS COMPUTING LANDSCAPE
Management Information Systems
Lecture 9 The Wireless Revolution
THE WIRELESS COMPUTING LANDSCAPE
Rate
4G
802.11b WLAN
3G
Other Tradeoffs:
Rate vs. Coverage
Rate vs. Delay
Rate vs. Cost
Rate vs. Energy
2G
2G Cellular
Mobility
Fundamental Design Breakthroughs Needed
Data rate comparison
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Evolution towards 4G
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Evolution towards 4G
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Internet Users
Management Information Systems
Lecture 9 The Wireless Revolution
How much data does it take…?
1. To watch one minute of a YouTube video?
a.
b.
c.
800 KB
100 MB
2 MB
2. To upload a photo to your Facebook page?
a.
b.
c.
7 MB
500 KB
1 GB
WirelessED: Created by Consumer Action. Sponsored by AT&T © Consumer Action 2011
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Data estimates for common
smartphone activities
Based on the data calculator from AT&T Mobility. Actual data used per activity can vary significantly.
WirelessED: Created by Consumer Action. Sponsored by AT&T © Consumer Action 2011
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Data estimates for common
smartphone activities
Activity/Function
Send/receive 1
text-only email
Send/receive 1 photo
email
Send/receive 1 email
w/doc attachment
View 1 Web page
Data Used
Activity/Function
Data used
20 KB
Stream 1 minute
of music
500 KB
350 KB
Stream 1 minute of
standard-quality video
2 MB
300 KB
Download 1 app, game
or song
4 MB
180 KB
Upload/download 1 file
to/from social media
500 KB
Based on the data calculator from AT&T Mobility. Actual data used per activity can vary significantly.
WirelessED: Created by Consumer Action. Sponsored by AT&T © Consumer Action 2011
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The Wireless Revolution
The Big 20-Year Change =
People Connected 24/7 with Mobile Devices
Chapter 6: The Internet
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© 2006 by Prentice Hall
Global PC Sales – 2015
• Global PC shipments totaled 276.2
million in 2015, a 10.4 percent plunge
from the 308.3 million recorded the
year before, research firm the
International Data Corporation (IDC),
said on Jan 12, 2016.
• It is the first time shipments have
dipped below 300 million since 2008.
• PC shipments continue downward
spiral for 4 successive years
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Management Information Systems
Lecture 9 The Wireless Revolution
THE WIRELESS COMPUTING LANDSCAPE
(where we buy 1.6 billion PCs every five years).
Chapter 6: The Internet
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Wireless Network
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Wireless Network
© 2006 by Prentice Hall
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
The Institute of Electrical and Electronics Engineers (IEEE)
established a hierarchy of complementary standards for
wireless computer networks.
Global Wireless Network Standards:
• IEEE 802.15 (Bluetooth) for the Personal Area
Network (PAN)
• IEEE 802.11 (Wi-Fi) for the wireless Ethernet Local
Area Network (LAN)
• IEEE 802.16 (WiMax) for the Metropolitan Area
Network (MAN)
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
Bluetooth
• Designed for personal use over short distances
• Low-bandwidth technology, with speeds of up to
722 Kbps
• Can link up to 8 devices in 10-m area
• Consumes very little power
• Devices can discover each other and exchange
information automatically
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
A Bluetooth Network (PAN)
Figure 9-5
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
Wi-Fi (Wireless Fidelity)
• Standards: 802.11a, 802.11b, 802.11g, 802.11n,
802.11ac
• 802.11“g” maxed out at 54 Mbps; and “n” offers
300 Mbps. The latest 802.11ac (Gigabit Wi-Fi)
offers more than 1 Gbps.
• Wireless Application Protocol (WAP): the wireless
equivalent of TCP/IP, uses Wireless Markup
Language (WML) and micro browsers
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
An 802.11 Wireless LAN
Figure 9-6
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS COMPUTER NETWORKS AND INTERNET ACCESS
Wi-Fi Tips
• If your high-speed Internet provider
offers bandwidth up to 100 Mbps, then
even with your 802.11n router, it will stay
at 100 Mbps.
• If there are 10 computers downloading
at full speed all the time, it will split the
Internet resources into 10 parts, with
everyone only able to have 10 Mbps at
once.
© 2006 by Prentice Hall
Cellular Data Services
• Portable Wi-Fi hotspot,
also known as MiFi, is a
brand name for a
compact, mobile,
wireless router offered
by Novatel Wireless
• Some cell phones, such
as the Droid X and
iPhone, can act as a
portable Wi-Fi hotspot
by becoming the router
for a wireless network
Chapter 6: The Internet
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Internet Tethering
• Tethering is when you turn you
smartphone into a mobile Wi-Fi
hotspot and share your
phones 3G/4G data
connection.
• You don't have to use Wi-Fi to
share your phone's internet
connection: some allow you
to connect a laptop (possibly
even a tablet) via a USB
cable.
Drawback? Data usage, Power drain
© 2006 by Prentice Hall
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
Wireless Supply Chain Management (SCM) and Radio
Frequency Identification (RFID)
• Wireless supply chain management systems:
Provide simultaneous accurate information about
demand, supply, production, and logistics as
goods move among supply chain partners
• Radio Frequency Identification (RFID) systems:
Provide a powerful technology for tracking the
movement of goods throughout the supply chain
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
How RFID Works
Figure 9-10
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
Wireless in Health Care
Wireless Applications:
• Electronic Medical Record (EMR) retrieval
• Wireless note taking for patient charts
• Lab test results
• Prescription generation
• Medical databases
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
Wireless Sensor Networks and Pervasive Computing
• Wireless sensor networks (WSNs): Networks of
interconnected wireless devices that are
embedded into the physical environment to
provide measurements of many points over large
spaces
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
Wireless Sensor Networks and Pervasive Computing
(Continued)
• Pervasive computing: Wireless technologies are
pushing computing into every facet of life,
including cars, homes, office buildings, tools and
factories; providing connections anywhere and
anytime.
Management Information Systems
Lecture 9 The Wireless Revolution
WIRELESS TECHNOLOGY IN THE ENTERPRISE
A Wireless Sensor Network
Figure 9-11
Source: From Jason Hill, Mike Horton, Ralph King, and Lakshman Krishnamurthy, “The Platforms Enabling Wireless Sensor
Networks,” Communications of the ACM 47, no. 6 (June 2004).
Management Information Systems
Lecture 9 The Wireless Revolution
MANAGEMENT OPPORTUNITIES, CHALLENGES, AND SOLUTIONS
Management Opportunities:
Wireless technology offers:
• Flexible business processes
• Business processes not limited by time or space
• New channel for communicating with client
• Source of new products and services
Management Information Systems
Lecture 9 The Wireless Revolution
MANAGEMENT OPPORTUNITIES, CHALLENGES, AND SOLUTIONS
Management Challenges:
• Integrating wireless technology into the firm’s IT
infrastructure
• Maintaining security and privacy
Management Information Systems
Lecture 9 The Wireless Revolution
MANAGEMENT OPPORTUNITIES, CHALLENGES, AND SOLUTIONS
Solution Guidelines:
The following are some of the guidelines for managing
mobile technology in the enterprise:
• Identifying areas in which wireless can provide
value
• Creating a management framework for wireless
technology
• Using a pilot program before full-scale rollout of
wireless systems