Introduction to Wireless Networking

Module-01Overview of Wireless Standards, Organizations and

Technology

Jerry BernardiniCommunity College of Rhode Island

04/19/23 1Wireless Networking J. Bernardini

Presentation Reference Material

• CWNA Certified Wireless Network Administration Official Study Guide

(PWO-104), David Coleman, David Westcott, 2009, Chapter-1

• Wireless Networking in the Developing World http://wndw.net

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Abbreviated Wireless Network History ??dates

• 1830: Professor Joseph Henry transmitted the first practical electrical signal.

• 1880: Maxwell’s Equations• 1905: Marconi• 1920: Radio Receivers• 1935: Television• 1941: Radar• 1958: Satellite• 1970: ALOHAnet• 1990: Internet• 1998: WLAN

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Why Study Wireless Networks? A Partial List

• Cordless phones• Wireless Voice over IP phones• Wireless print servers• Wireless access points, routers, and bridges• Radio Frequency Identification devices• Wireless presentation gateways• Wireless conferencing systems• Laptop computers, PDAs, and other mobile wireless client• device

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Wireless Industry Guided by Three Categories of Organizations

• Regulation- Boundaries of Operation– Federal Communications Commission (FCC)– European Telecommunications Standards Institute (ETSI)

• Power limits and Frequencies

• Standardization- How systems work together– Institute of Electrical and Electronics Engineers (IEEE)

• 802.11 a, b, g, n

• Compatibility – Tests for interoperability– Wi-Fi Alliance

• If you buy Wi-Fi certified gear it work with other Wi-Fi gear

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FCC - Federal Communications Commission

• Regulatory Bodies – City, State, Country• FCC- Born in 1934 to regulate radio, television, cable,

satellite and wire communications• FCC regulates

– Radio frequencies– Output power levels– Indoor and Outdoor usage

• Every country has regulatory bodies

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FCC Wireless Bands• 1985:Industry, Scientific and Medical Industrial

License-Free Bands – ISM Bands– 900 MHz band, (900 to 928 MHz range)– 2.4 GHz band, (2.4 to 2.483 GHz range)– 5 GHz band, (5.725 to 5.850 GHz range)

• 1997: Unlicensed National Information Infrastructure U-NII bands– 5.15 to 5.25 GHz– 5.25 to 5.35 GHz– 5.725 to 5.825 GHz

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FCC Unlicensed Bands

Advantages Disadvantages•No licenses required•No Fees•No Permits•Comply with rules and build anything

•Everyone can use the bands•Interference between users•Bandwidth Contention•First-come-first –serve•Interference from late-comers

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FCC Regulates Frequencies

• Frequencies are grouped into bands– Wireless LAN bands include: (Hz = Hertz)

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Frequency Band Total Bandwidth License-Free Band

2400–2500 MHz 100 MHz ISM

5.15–5.25 GHz 100 MHz U-NII

5.25–5.35 GHz 100 MHz U-NII

5.470–5.725 GHz 255 MHz U-NII

5.725–5.825 GHz 100 MHz U-NII

FCC Power Output Limits-U-NI Bands

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Band Power Output Limits Area Usage

U-NII 5.15–5.25 GHz 40 mW Restricted to indoor operations

U-NII 5.25–5.35 GHz 200 mW Indoor/outdoor

U-NII 5.470–5.725 GHz 200 mW Indoor/outdoor

U-NII 5.725–5.825 GHz 800 mW Higher output power assumes outdoor operations

mw = 1/1000 watt

Non-USA Standard Organizations

• OfCom-Office of Communication –United Kingdom• MIC- Ministry of Internal Affairs and

Communications-Japan• ARIB-Association of Radio and Businesses – Japan• ACMA-Australian Communications and Media

Authority

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International Telecommunications Union Radiocommunications Sector (ITU-R)

• 1947: United Nations creates ITU-R to:– Promote cooperation and technical development

• ITU-R maintains a database of frequencies with five administrative regions– Region A: The Americas– Region B: Western Europe– Region C: Eastern Europe– Region D: Africa– Region E: Asia and Australia

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Institute of Electrical and Electronics Engineers - IEEE (Eye-triple-E)

• World’s leading non-profit professional organization for the advancement of technology

• Mission – – promote “the engineering process of creating, developing, integrating,

sharing, and applying knowledge about electronics and information technologies and sciences for the benefit of humanity and the profession.”

• 350,000 individual members in 150 countries.• Nearly 900 active standards with 700 under

development.

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IEEE Wireless Standards

• IEEE 802 project is the most important with multiple working groups– IEEE 802.3 (Ethernet)– IEEE 802.11 Wireless LAN (WLAN)– IEEE 802.16 WiMAX– IEEE 802.16 Mobile Broadband

• Most of this course will deal with IEEE 802.11

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IEEE 802.11 Standards

• 1997: First 802.11 ratified (802.11-1997)• Three ways of implementing a physical

communications layer (PHY)– Frequency-hopping spread spectrum (FHSS)– Direct-sequence spread spectrum (DSSS)– Infrared communications (not implemented extensively)

• All operate at 1Mbps and 2Mbps• To be covered in depth is subsequence lessons

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IEEE 802.11 Amendments

• IEEE 802.11a – OFDM, 5 GHz U-NII, 54 Mbps• IEEE 802.11b – DSSS, 2.4 Mhz ISM band, 11 Mbps• IEEE 802.11c – Bridging operation• IEEE 802.11d – regularity specifications• IEEE 802.11e – Quality of Service (QoS)• IEEE 802.11F- access point re-association• IEEE 802.11g – DSSS/OFDM, 2.4 Mhz, 54 Mbps• IEEE 802.11h – Dynamic frequency, power control• IEEE 802.11i – important security enhancements

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IEEE 802.11 Amendments

• IEEE 802.11j – 4.9-5 Mhz band in Japan• IEEE 802.11k – channel management above 5 Mhz• IEEE 802.11n –Important 100 Mbps plus WLAN• IEEE 802.11p –Intelligent Transportation Systems• IEEE 802.11r – Roaming amendment• IEEE 802.11s – Extended Mesh network interoperate• IEEE 802.11T – measurement and test conditions• IEEE 802.11u – handoffs between WiMax and WLAN• IEEE 802.11v – device management• IEEE 802.11w – improved management frames04/19/23 Wireless Networking J. Bernardini 17

More IEEE Standards

• IEEE 802.1X – port-based authentication for security• IEEE 802.3-2005 Clause 33 – defines power over

Ethernet (PoE)• IEEE 802.1D – bridging priority• IEEE 802.1Q – priority tagging and VLAN FOR QoS

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IETF – International Engineering Task Force

• Primarily a volunteer organization• The most important standards organization for the

Internet operation• Operates on the basis of the Request-For-Comment

(RFC)– IETF issues an RFC in a technical issue– After a period of time all responses to the RFC are gather and voted on

• WLAN RFC 3748, RFC 2865 are important for wireless– RFC 3748 - WLAN security– RFC 2865 -security and the use of RADIUS server

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Wi-Fi Alliance

• Certification organization for testing and interoperability

• Eight basic Wi-Fi CERTIFIEDTM programs• Wi-Fi is just a marketing name; it does not stand for

anything• Before October 2002 know as the Wireless Ethernet

Compatibility Alliance (WECA)• Most commercial products will have a Wi-Fi logo• www.wi-fi.org for more information

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Wi-Fi CERTIFIEDTM Programs• IEEE 802.11 baseline – meets up to IEEE 802.11n • Wi-Fi Protected Access 2 (WPA2) – based upon IEEE 802.11i• Wi-Fi Multimedia (WMM)- QoS for various applications• WMM Power Save(WMM-PS) – specifications to save battery

power• Wi-Fi- Protection -Security – Simplified and automated WPA

and WPA2 security setup• CWG-RF multimedia- defines performance for cellular radios

and handsets• Voice Personal-application – support for personal and

business voice applications

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Communications Models

• Models are design, management, interoperability and learning

• OSI Model - seven layers- can be abstract but is very commonly used

• Core-Distribution-Access Model – a useful model for wireless networking

• TCP/IP Model - Four layers – good for networks built around TCP/IP

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OSI Model

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Core – Distribution - Access

• Core Layer – Does not route or manipulate traffic– High speed traffic – think superhighway– Backbone of network– High speed switches and routers

• Distribution Layer – Routes or directs traffic other nodes – Medium speed traffic – think city traffic– Routers and Bridges

• Access Layer – directs traffic to end user– Relative slower traffic – think local street traffic– Access Points and Switches

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Core – Distribution – Access Details

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TCP/IP Model

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(Transport)

TCP/IP and OSI Model Maping

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CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 28

Modulation

• Carrier signal is a continuous electrical signal– Carries no information

• Three types of modulations enable carrier signals to carry information– Height of signal– Frequency of signal– Relative starting point

• Modulation can be done on analog or digital transmissions

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Analog and Digital Modulation

• Analog Transmission use analog carrier signals and analog modulation.

• Digital Transmission use analog carrier signals and digital modulation.

• Modem (MOdulator/DEModulator): Used when digital signals must be transmitted over analog medium– On originating end, converts distinct digital signals into

continuous analog signal for transmission– On receiving end, reverse process performed

• WLANs use digital modulation of analog signals (carrier signal)

CWNA Guide to Wireless LANs, Second Edition CCRI J. Bernardini 30

Analog vs. Digital Transmissions

Digital Signal = A signal in which information is carried in a limited number of different discrete states or levels; High/Low, One/Zero, 1/0

Analog Signal = A signal that has continuously varying voltages, frequencies, or phases. All amplitude values are present from minimum to maximum signal levels.

CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 31

Frequency and Period

CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 32

Analog Modulation

• Amplitude: Height of carrier wave• Amplitude modulation (AM): Changes amplitude so

that highest peaks of carrier wave represent 1 bit while lower waves represent 0 bit

• Frequency modulation (FM): Changes number of waves representing one cycle– Number of waves to represent 1 bit more than number of waves to

represent 0 bit

• Phase modulation (PM): Changes starting point of cycle– When bits change from 1 to 0 bit or vice versa

CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 33

Digital Modulation• Advantages over analog modulation:

– Better use of bandwidth– Requires less power– Better handling of interference from other signals– Error-correcting techniques more compatible with other digital

systems

• Unlike analog modulation, changes occur in discrete steps using binary signals– Uses same three basic types of modulation as analog

Amplitude shift keying (ASK)

CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 34

Digital Modulation

Frequency shift keying (FSK)

Phase shift keying (PSK)