Wireless Technology. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives Explain the principles of radio.

Wireless Technology

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

Wireless Media

Referred to as unbounded media

Electronic signal

Media type

General classification

Wireless

Atmosphere

Radio waves Infrared Microwave


Wireless Media

Spread throughout atmosphere

Electronic signal

Media type


Wireless

Atmosphere



Wireless Media

Not limited to a single path

Electronic signal

Media type


Wireless

Atmosphere



Electromagnetic Waves

Categorized according to frequency ranges Frequency is based on repeating pattern of

waveform

One complete waveform is a cycle Frequency is the number of times a cycle occurs

in one second


Radio and Microwave Transmission (Cont.)

Demodulation occurs after carrier wave and voice wave are received

Channel is identified by the assigned frequency


Infrared Transmission

Uses a series of digital light pulses Television remote control

Personal digital assistants

Laptops

Disadvantages Devices must be in direct line of sight of each other Can be used only for short distances


Radio Interference

Can be caused by: Virtually any type of electrical equipment Faulty electrical equipment Close proximity A powerful signal Industrial, Scientific, and Medical (ISM) band


ISM Band


Signal Reflection

A reflected radio signal can combine with the intended radio signal and either disrupt the intended signal or enhance it


Antenna Styles

The two major classifications are omni-directional and directional

Classification Description Related Antenna Styles

Omni-directional Transmits electromagnetic signals in all directions

Omni

Directional Transmits electromagnetic signals in a focused or aimed direction

DipoleYagiFlat panelParabolic


Antenna Styles (Cont.)


Radio Waves and Networks

Radio waves used in LANs Adhere to IEEE 802.11 and Bluetooth standards Operate at 2.4GHz


Radio Wave-Based Transmission Techniques

Spread spectrum refers to transmission channels spread across the spectrum of available bandwidth Frequency hopping – data that is transmitted

simultaneously on multiple channels Direct sequencing data that is transmitted sequentially

on multiple channels Orthogonal frequency-division multiplexing (OFD

M) communicates wireless data over several different channels within an assigned frequency range


Frequency Hopping Spread Spectrum (FHSS)


Direct Sequencing Spread Spectrum (DSSS)


In class lab

Labsim Wireless Network Configuration 6.44 – 6.47

NEXT CLASS

LabSim 6.3-6.3.4, 6.4.1-6.4.3


Radio Wave-Based Transmission Techniques

Orthogonal frequency-division multiplexing (OFDM) communicates wireless data over several different channels within an assigned frequency range


FCC U-NII Classifications

FCC divided the 5 GHz radio frequency into three, 20-MHz channels called the Unlicensed National Information (U-NII) Infrastructure

Each U-NII classification has a frequency range of 100 MHz

Classification Frequency Range

U-NII 1 5.15 GHz–5.25 GHz

U-NII 2 5.25–5.35 GHz

U-NII 3 5.75 GHz–5.825 GHz


Radio Wave-Based Networking

Wireless Access Point (WAP) provides access to hardwired devices such as printers and routers

WAP controls flow of communication

All WAPs use same Service Set Identifier (SSID)

SSIDs should be changed to enhance security


Wireless Network Modes

Infrastructure mode – a wireless network that contains one or more access points

Ad hoc mode – a wireless network that does not contain an access point

IEEE 802.11 Standard uses terms Basic Service Set (BSS) wireless devices connected as and infrastructure / SSID

Independent Basic Service Set (IBSS) direct connection between 2 wireless devices

Extended Service Set Identifier (ESSID) allows user to keep connection while moving around the location

Devices need to be Wi-Fi compliant


IEEE 802.11 Standards

IEEE Classification

Assigned Frequency Maximum Data Rate

Transmission Method

802.11a 5 GHz 54 Mbps OFDM

802.11b 2.4 GHz 11 Mbps DSSS

802.11g 2.4 GHz5 GHz

11 Mbps (802.11b mode)54 Mbps (802.11g mode)

DSSS

OFDM

802.11n 2.4 GHz5 GHz

54 Mbps (802.11a mode)11 Mbps (802.11b mode)54 Mbps (802.11g mode)300 Mbps (802.11n mode)

OFDM


802.11n

Latest 802.11 wireless network topology Multiple Input Multiple Output (MIMO) MIMO increases data transmission rate by using

spatial multiplexing Prior to MIMO, WAPs sent single stream of data

between transmitter and receiver


CSMA/CA Process

Carrier sense multiple access with collision avoidance


Overlap Area

Ad-hoc overlap area Infrastructure mode overlap area


Extending Wireless Network Range with WAPs


Extending Wireless Network Range with Cabling


New IEEE Wireless Standards

Working group—Standards that are still under development

Also known as Wireless Personal Network (WPAN)

IEEE 802.16 is working group hoping to: Achieve data rates as high as 70 Mbps over distances

of 30 miles or more Expand the radio frequencies assigned by the FCC


New IEEE Wireless Standards (Cont.)

Wireless USB connects devices wirelessly to transfer data between a PC and devices such as cameras, printers, and mobile phones, among others

Bluetooth, or piconet a personal network Short-range wireless system designed for limited

distances Does not interfere with 802.11b devices


Wireless Technology

Advantages Disadvantages

• Cost-effective compared to cable-based network media

• Easy to install• Appropriate for mobile

devices

• Affected to various degrees by atmospheric conditions

• Security because wireless transmissions can be intercepted


Wireless Security

IEEE 802.1x draft standard for wireless network Extensible Authentication Protocol (EAP) uses

exchange of username and password PEAP is improved version of EAP

Wired Equivalent Privacy (WEP) uses encryption keys to secure data sent over wireless networks


Wireless Security (Cont.)

Wi-Fi Protected Access (WPA) WPA-PSK (Pre-shared Key) is variation of WPA WPA-2 is improved version of WPA

Wireless Application Protocol (WAP) combines authentication and encryption


IEEE 802.1x Authentication and Encryption Protocols

IEEE 802.1x Authentication IEEE 802.1x Encryption

Extensible Authentication Protocol (EAP)

Wired Equivalent Privacy (WEP)

Protected EAP (PEAP) Wi-Fi Protected Access (WPA)Wi-Fi Protected Access-Pre-Shared Key (WPA-PSK)Wi-Fi Protected Access 2 (WPA-2)Wi-Fi Protected Access (WAP)


Windows Vista Wireless Network Properties


Exam 4 Review 10/30/2013Understand the concept of a carrier waveUnderstand the concept of infrared data transmissionUnderstand the regulation of frequency assignments in the U.SUnderstand what the ISM is used forKnow the various antenna styles and their usesWhat is frequency hoppingWhat are the various data transmission techniquesUnderstand how radio transmission can be sentUnderstand the OFDM transmission techniqueWhat is the function of a WAPUnderstand the frequencies of 802.11B – N and their transmission, access, and authentication methods and throughput ratingsUnderstand the communication process of WEPUnderstand the communication process of WPAKnow the types of wireless network systems and how they are identifiedKnow the various types of wireless network configurationHow does distance affect wireless communicationUnderstand the concept of bit rate Know what is sampling frequency, Latency, Jitter, VOIP, QOS, Understand which protocols are used for VOIP, multimedia streaming, audio and video transmission,data delivery


In class lab

Roberts Lab 17

NEXT CLASS

Test 4


Radio wave and microwave transmission use a _____ to carry data.

carrier wave

Review


Which of the following does not describe a carrier wave?

A. Identified by a frequency number

B. Mixed with a data signal

C. Consist of a varying frequency

D. Is a set frequency

C. Consist of a varying frequency

Review


A simple radio transmission consists of a _____ and _____.

transmitter, receiver

Review


The _____ produces the carrier wave and modulates the data signal into the carrier wave.

transmitter

Review


The _____ receives the modulated wave and demodulates it.

receiver

Review


The bandwidth of a carrier wave is referred to as a(n) _____.

channel

Review


A radio station number, such as 104.5, is referred to as a(n) _____.

channel

Review


A(n) _____ type antenna transmits radio signals in all directions.

A. Dipole

B. Omni

C. Parabolic

D. Yagi

B. Omni

Review


The _____ type antenna is typically used as a client or receiver.

A. Dipole

B. Omni

C. Parabolic

D. Yagi

A. Dipole

Review


Which of the following antenna types is not used for point-to-point links.

A. Flat panel

B. Omni

C. Parabolic

D. Yagi

B. Omni

Review


Which of the following is not a spread spectrum transmission technique?

A. Direct sequencing

B. Frequency hopping

C. Orthogonal frequency-division multiplexing (OFDM)

C. Orthogonal frequence-division multiplexing (OFDM)

Review


The _____ transmission technique uses multiple channels to transmit data sequentially.

A. direct sequencing

B. frequency hopping

C. Orthogonal Frequency-Division Multiplexing

A. direct sequencing

Review


The FCC divided the 5-GHz radio frequency into three, _____-MHz channels and classified them as the U-NII.

A. 10

B. 20

C. 40

D. 60

B. 20

Review


Each U-NII classification has a frequency range of _____MHz

A. 100

B. 200

C. 400

D. 600

A. 100

Review


A(n) _____ wireless network consists of two or more computers with wireless network adapters.

Ad-hoc

Review


A(n) _____ wireless network consists of one or more Wireless Access Points.

infrastructure

Review


A(n) _____ provides a connection between a cable-based network and a wireless network.

Wireless Access Point or WAP

Review


IEEE 802.11 wireless networks use the _____ media access method.

A. CSMA/CA

B. CSMA/CD

C. token passing

D. dual-ring

A. CSMA/CA

Review


A(n) _____ is used to identify a wireless network and is similar to a workgroup or domain name.

Service Set Identifier or SSID

Review


For security purposes in a wireless network, what should be done?A. The WAP should be connected to a cable-

based networkB. The manufacturer’s settings should be

unchanged because they provide the highest security

C. WEP encryption should be used to secure transmitted data

D. The default SSID should be changed

D. The default SSID should be changed

Review


Which of the following does not describe the Bluetooth standard?A. Designed for long-range wireless network

communications.B. Bluetooth devices must be in direct line of

sight.C. Uses 79 channels and frequency hopping

spread spectrum, starting at 2.4 GHz.D. Does not interfere with 802.11b devices.

A. Designed for long-range wireless network communications.

Review


Cellular technology based on radio waves connecting to designated areas called _____.

A. cells

B. channels

C. ESSIDs

D. WPANs

A. cells

Review


Which of the following is not a disadvantage of wireless networking? (Select all that apply)

A. Difficult to install

B. Affected to various degrees by atmospheric conditions

C. Wireless transmissions can be intercepted

D. Costly compared to cable-based networks

A, D

Review

Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc.

Ad hoc mode A wireless network that does not contain a Wireless

Access Point. Basic Service Set (BSS)

An IEEE term used to describe a group of wireless devices connected as an infrastructure network or an SSID.

Carrier wave An electromagnetic wave of a set frequency that is

used to carry data.

Glossary


Cellular technology A technology based on radio waves connecting to

designated areas referred to as cells. Channel

The bandwidth of a carrier wave. Demodulation

The process of separating a data signal from a carrier wave.

Direct sequencing A spread spectrum technique that transmits data on

multiple channels sequentially.

Glossary


Frequency hopping A spread spectrum technique that transmits data on

multiple channels simultaneously. Geosynchronous orbit

An orbit in which a satellite’s rotational speed is synchronized with the earth’s rotational speed, making the satellite appear to be in a stationary position.

Independent Basic Service Set (IBSS) A network that does not use an access point and

usually is a direct connection between two wireless devices.

Glossary


Infrastructure mode A wireless network that contains one or more

Wireless Access Points. ISM band

The band of radio frequencies associated with industrial, scientific, and medical devices.

Modulation The process of mixing a data signal with a carrier

wave.

Glossary


Multiple Input Multiple Output (MIMO) A wireless networking technology that transmits two

or more streams of data to increase data throughput and the range of the wireless network.

Omni-directional The ability of an antenna to transmit electromagnetic

signals in all directions.

Glossary


Orthogonal frequency-division multiplexing (OFDM) A transmission technique that transmits data over

different channels within an assigned frequency range. Each channel is broadcast separately and is referred to as multiplexed. It can achieve data rates as high as 54 Mbps.

Piconet A Bluetooth network. Also called a Personal Area

Network (PAN). Propagation delay

The time it takes for data to be transmitted from the earth and satellite.

Glossary


Radio interference Interference that matches the frequency of a carrier

wave. Radio waves

Electromagnetic waves with a frequency range of 10 kHz to 3,000,000 MHz.

Receiver An electronic device that receives a modulated

signal and demodulates it. Spatial multiplexing

A wireless networking technology that transmits two or more streams of data in the same frequency channel.

Glossary


Spread spectrum A transmission technique that uses multiple channels

to transmit data either simultaneously or sequentially.

Transmitter An electronic device that generates a carrier wave

and modulates the data signal into the carrier wave. Unbounded media

An unrestricted path for network transmissions.

Glossary


Wi-Fi Protected Access (WPA) A protocol that combines the authentication method

with encryption. Wi-Fi

A term coined by the Wi-Fi Alliance that refers to 802.11 wireless network products.

Wired Equivalent Privacy (WEP) A data encryption protocol that makes a wireless

network as secure as a wired network.

Glossary


Wireless Access Point (WAP) A wireless network device that provides a connection

between a wireless network and a cable-based network and controls the flow of all packets on the wireless network.

Wireless Application Protocol (WAP) A protocol that ensures the safe exchange of data

between a wireless network and a portable Wi-Fi device, such as a cell phone. It uses a set of keys to identify a device and to encrypt the data exchanged.

Glossary


Wireless Personal Area Networks (WPAN) A small Ethernet network consisting of personal

wireless devices such as a cell phone, laptop, palmtop, wireless printer, Wireless Access Point, iPod, Xbox 360, and similar items.

Working group A standard not fully developed and adopted as an

official standard recognized by IEEE.

Glossary

Wireless Technology. Permission granted to reproduce for educational use only.© Goodheart-Willcox Co., Inc. Objectives Explain the principles of radio.

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