Introduction to wireless standards.

Page 2

Instructor, PACE-IT Program – Edmonds Community College

Areas of Expertise Industry Certifications

PC Hardware

Network Administration

IT Project Management

Network Design

User Training

IT Troubleshooting

Qualifications Summary

Education

M.B.A., IT Management, Western Governor’s University

B.S., IT Security, Western Governor’s University

Entrepreneur, executive leader, and proven manger with 10+ years of experience turning complex issues into efficient and effective solutions.

Strengths include developing and mentoring diverse workforces, improving processes, analyzing business needs and creating the solutions required— with a focus on technology.

Brian K. Ferrill, M.B.A.

Page 3

Introduction to wireless standards.PACE-IT.

– CSMA/CA.

– Wireless standards.

Page 4

CSMA/CA.Introduction to wireless standards.

Page 5

All wireless Ethernet standards employ an algorithm called carrier sense multiple access with collision avoidance (CSMA/CA).

A CSMA/CA network involves a method of transmission that avoids packet collisions. Once a node wants to send a packet, it listens to the carrier wave. If no other node is transmitting, it will then transmit. If another node is transmitting, it will wait a random amount of time and then listen to the carrier wave again.

This differs from a CSMA/CD (collision detection) type of network, which is all about how to transmit after a collision has occurred.

CSMA/CA.Introduction to wireless standards.

Page 6

CSMA/CA.Introduction to wireless standards.

– Frequency modulation.» Frequency modulation is the process used to encode

data into a carrier wave.• 802.11 uses two main frequency modulation methods.

– Orthogonal frequency-division multiplexing (OFDM).

» OFDM is a frequency division multiplexing scheme that uses multiple sub-carrier channels to carry data.

» OFDM is used to mitigate against attenuation (loss of signal strength over distances) and multipath issues that exist in networking.

– Direct-sequence spread spectrum (DSSS).

» DSSS is a modulation technique that uses spread spectrum technology to affect data transfer.

» DSSS is used to mitigate the problem of multiple users on a channel and for effective timing between the transmitter and receiver.

Page 7

Wireless standards.Introduction to wireless standards.

Page 8

Wireless networking standards are established by the 802.11 committee of the Institute of Electrical and Electronics Engineers (IEEE).

Quite often, the term “Wi-Fi” (or “WiFi”) is used to describe an 802.11 network, which is technically incorrect. Wi-Fi is actually a reference to the Wi-Fi Alliance, which is responsible for certifying that wireless networking equipment actually meets the 802.11 standards. Wi-Fi has become synonymous with the Wireless Local Area Network (WLAN) in the English language.

Wireless standards.Introduction to wireless standards.

Page 9

Wireless standards.Introduction to wireless standards.

– 802.11a.» Max speed: 54 Mbps on 5 GHz frequency.» Uses OFDM modulation.» Max distance: 150 ft.» Compatibility: 802.11a/ac.

– 802.11b.» Max speed: 11 Mbps on 2.4 GHz frequency.» Uses DSSS modulation.» Max distance: 300 ft.» Compatibility: 802.11b/g/n.

– 802.11g.» Max speed: 54 Mbps on 2.4 GHz frequency.» Uses OFDM and DSSS modulation.» Max distance: 300 ft.» Compatibility: 802.11b/g/n.

Page 10

Wireless standards.Introduction to wireless standards.

– 802.11n.» Max speed: 600 Mbps on 2.4/5 GHz frequencies.» Uses OFDM modulation.» Max distance: 300 ft.» Compatibility: 802.11b/g/n.» MIMO: four antennas (up to four spatial streams).

– 802.11ac.» Max speed: 433 Mbps up to multiples of Gbps on 5 GHz

frequency.» Uses OFDM modulation (an advanced implementation).» Max distance: theoretical 300 ft.» Compatibility: 802.11a/g/n/ac.» MIMO: eight antennas (up to eight spatial streams).

Page 11

What was covered.Introduction to wireless standards.

CSMA/CA is an algorithm used in wireless networks to avoid packet collisions—as opposed to that used on wired networks, which works to detect collisions. There are two main frequency modulation processes for wireless networks, OFDM and DSSS, which are used to encode data on the RF carrier wave.

Topic

CSMA/CA.

Summary

The IEEE’s 802.11 committee sets the commonly accepted wireless network standards. Wi-Fi is actually a reference to the Wi-Fi Alliance—the organization that certifies that equipment meets the 802.11 standards. The 802.11a standard is only compatible with itself and operates in the 2.4 GHz frequency. Equipment built using the 802.11b/g/n and 802.11ac standards can all be used effectively in the same environment; some of these standards can operate in the 5 GHz frequency. Each standard has a theoretical maximum throughput. MIMO is used to increase throughput and to reduce weak spots or dead zones in a wireless network.

Wireless standards.

Page 12

THANK YOU!

This workforce solution was 100 percent funded by a $3 million grant awarded by the U.S. Department of Labor's Employment and Training Administration. The solution was created by the grantee and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties, or assurances of any kind, express or implied, with respect to such information, including any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability or ownership. Funded by the Department of Labor, Employment and Training Administration, Grant #TC-23745-12-60-A-53.

PACE-IT is an equal opportunity employer/program and auxiliary aids and services are available upon request to individuals with disabilities. For those that are hearing impaired, a video phone is available at the Services for Students with Disabilities (SSD) office in Mountlake Terrace Hall 159. Check www.edcc.edu/ssd for office hours. Call 425.354.3113 on a video phone for more information about the PACE-IT program. For any additional special accommodations needed, call the SSD office at 425.640.1814. Edmonds Community College does not discriminate on the basis of race; color; religion; national origin; sex; disability; sexual orientation; age; citizenship, marital, or veteran status; or genetic information in its programs and activities.