Page 170 - DCAP311_DCAP607_WIRELESS_NETWORKS

Wireless Networks

Notes 10.6 Summary

IEEE 802.11 is a set of physical layer standards for implementing wireless local area
network (WLAN) computer communication in the 2.4, 3.6, 5 and 60 GHz frequency bands.
The 802.11 family consist of a series of half-duplex over-the-air modulation techniques that use
the same basic protocol. The most popular are those defined by the 802.11b and 802.11g protocols,
which are amendments to the original standard. 802.11-1997 was the first wireless networking
standard

The 802.11 standard is defined through several specifications of WLANs.
Wi-Fi systems are half duplex shared media configurations where all stations transmit and
receive on the same radio channel
One business that grew out of Wi-Fi was the Wireless ISP (WISP). This is the idea of selling an
Internet access service using wireless LAN technology and a shared Internet connection in a
public location designated a hot spot.
10.7 Keywords

IEEE 802.11: is a set of physical layer standards for implementing wireless local area
network (WLAN) computer communication in the 2.4, 3.6, 5 and 60 GHz frequency bands.
802.11a: This is an extension to 802.11 that pertains to wireless LANs and goes as fast as 54 Mbps
in the 5-GHz band
802.11b: The 802.11 high rate Wi-Fi is an extension to 802.11 that pertains to wireless LANs
and yields a connection as fast as 11 Mbps transmission (with a fallback to 5.5, 2, and 1 Mbps
depending on strength of signal) in the 2.4-GHz band.
802.11g: This pertains to wireless LANs and provides 20+ Mbps in the 2.4-GHz band.
Wi-Fi Multimedia Extensions (WME): This uses a protocol called Enhanced Multimedia
Distributed Control Access (EDCA), which is Extensions an enhanced version of the Distributed
Control Function (DCF) defined in the original 802.11 MAC.

10.8 Review Questions

1. What are the various specifications in the 802.11 family?
2. Do a technical camparsion between the three major wi-fi standards
3. What are the two operating modes that are included in the 802.11e standard?
4. Explain the two primary radio transmission techniquesof the wi Di system.
5. Discuss the issues which are assumed to be the cause of the sluggish adoption of wi-fi
technology
6. Distinguish between the ieee 802.16a and 802.11 standards - wifi versus wimax scalability.

Answers: Self-Assessment

1. wireless networking technology 2. 2.4 radio
3. Hacker 4. Adaptive

5. 802.11b

164 LOVELY PROFESSIONAL UNIVERSITY