Week6 - Intro 2 Wireless Com

8/2/2019 Week6 - Intro 2 Wireless Com

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Week 6 Wired & Wireless

Communication

Presentation by Kwame Tweneboah-Koduah (SOT, GIMPA)


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Wired & Wireless Communication



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Objectives

Define bandwidth and discuss the bandwidthneeds of typical users.

Discuss how modems transform digital computersignals into analog signals.

List transmission media and explain severaltransmission methods.



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Objectives Provide examples of how digitization and

convergence are blurring the boundaries thatdistinguish popular communications devices,

including phones and computers.

Discuss variouswired and wireless applications.



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Moving Data:

Bandwidth and Modems Communications is the process of sending and

receiving messages electronically between twopoints.

Acommunications channel is a path used tosend and receive messages.



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Moving Data:

Bandwidth and ModemsAnalog signals are continuous waves.

Digital signals are discontinuous, discrete pulses.

Converters translate signals.



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Moving Data:

Bandwidth and Modems


Digital signal sampling


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Moving Data:

Bandwidth and Modems Bandwidth is the maximum amount of data

transmitted through a communication channel atone time.

Throughput is the actualamount of datatransmitted.

Broadband is any transmission medium thatcarries several channels to transport data at highspeeds.



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Moving Data:

Bandwidth and ModemsAmodem is a communication device used to send

and receive data between different transmissionsystems.

The sender uses modulation to transmit digitalsignals.

The receiver uses demodulation to return signals todigital form.

The term modem comes from modulate anddemodulate.



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Moving Data:

Bandwidth and Modems



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Moving Data:

Bandwidth and Modems Types of modems

Analog

Digital subscriber line (DSL)

Cable

Integrated Services Digital Network (ISDN)

The data transfer ratethe rate at which two

modems exchange datais measured in bits persecond (bps).



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Wired Transmission Media

Twisted pair wire is copper wire used fortelephone and data communication.

Two pairs of interweaved wires twisted together Inexpensive, but bandwidth too low for video, voice,

and data at the same time



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Wired Transmission Media


Coaxial cable consists ofcopper wire surrounded by

insulation and braidedwire.

Broadband communication

Cable TV

10 Mbps transfer rate


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Wired Transmission MediaFiber-optic cable consists of

thin strands of glass or plastic

that carry data through pulsesof light.

Broadband communication

10 Gbps transfer rate



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Wireless Transmission Media

Sending and receivingdevices must be in line ofsight.

Use an IrDA port toenable data transfer.


Infrared is a wireless transmission medium thatcarries data through the air using light beams.


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Wireless Transmission Media Radio transmission enables music, photos, and

voice to travel through the air as radio frequency orradio waves. Bluetooth radio transmission enables devices within

30 feet to communicate wirelessly. Does not require direct line of sight.



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Wireless Transmission Media



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Wireless Transmission Media Microwaves transmit data via electromagnetic radio

waves with short frequencies.



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Wireless Transmission Media Satellites are microwave relay stations in

space that transmit data through microwave

signals. Direct broadcast satellite (DBS) is a consumer

satellite technology that receives digital TVsignals through a reception dish.


d


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Wired Communication

via the PSTN

Public switched telephone network (PSTN) Worldwide telephone system used for data

and voice communications

Primarily digital

Subscriber loop carrier (SLC) Links home and business telephones

Accommodates analog devices Local loop is the area served by an SLC.


Wi d C i i


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Wired Communication

via the PSTN

Wi d C i i


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Digital telephony

Telephones and transmissions are digital.

Companies use a private branch exchange (PBX).

Multiplexing

Allows multiple calls over a single line.

Long-distance carriers transmit many calls in digitalformat in a single circuit.


Wired Communication

via the PSTN

Wi d C i ti


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Wired Communication

via the PSTN

Wi d C i ti


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Last-mile technologies

Cable-based broadband

Provides Internet access through cable TV connections

Uses cable modems to obtain higher speeds than DSL

Leased lines

Specially conditioned telephone lines, such as T1 lines,between two points


Wired Communication

via the PSTN


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Convergence:

Is It a Phone or a Computer?

Convergence is blending: Multiple industries such as

computers, consumer electronics, andtelecommunications

Products such as personal computersand telephones


Digitization is the process of transforming datainto a digital form.

C


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Cellular telephones

Digital transmission of voice, text, images, and video.

Classified by generations; 3G (third generation) is the

current generation. A network of transmitters called cell sites broadcasts

signals throughout geographic areas called cells.


Convergence:


Convergence


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Web-enabled devices

Display and respond to markup languages, such asHTML and XML, that are used to build Web pages.

Examples PDAs

Smartphones

Notebooks


Convergence:



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Wired and Wireless Applications Internet telephony, or VoIP (Voice over Internet

Protocol)

Offers computer-to-phone and phone-to-phone

transmission through the Internet Placing calls requires:

A computer with a microphone and speakers orheadphones

An Internet connection A telephone-enabled program



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Wired and Wireless Applications


Internet telephony

Videoconferencing transmits sound and video

images to people in different locations using: Video camera

Skype software


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Wired and Wireless Applications Satellite technology

Satellite radio

Is not affected by location, distance, or obstructions

Uses satellites orbiting the Earth Permits usage in areas with restricted local radio stations

or bad AM/FM reception



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Wired and Wireless ApplicationsSatellite technology

GPS (Global Positioning System)

A system of 27 satellites that allows a GPS receiverto pinpoint a location

Mobile units for cars

Installed car systems, such as OnStar



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Text messaging is using

a cell phone forapplications previouslyused on computers

Instant messaging

Brief e-mail


Text and picture messaging


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Picture messaging

Transmits color pictures and backgrounds Cellular telephone acts as a camera


Text and picture messaging


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Wired and Wireless Applications Surfing safely at public wireless hot spots

Use firewalls and antivirus software.

Use legitimate networks to avoid evil twins.

Do not perform financial transactions.

Select appropriate operating system settings to avoidbeing detected.


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Week6 - Intro 2 Wireless Com

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