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Manmohan Sharma, Lovely Professional University Unit 4: Wireless Networks Types and PAN Technologies

Unit 4: Wireless Networks Types and PAN Technologies Notes

CONTENTS

Objectives
Introduction
4.1 Types of Wireless Networks
4.1.1 WPAN (Wireless Personal Area Network)
4.1.2 WLAN (Wireless Local Area Network)
4.1.3 Wireless Metropolitan Area Network (WMAN)

4.2 Wireless PAN Technologies (WPAN)
4.2.1 IEEE 802.15
4.2.2 Bluetooth
4.3 Summary

4.4 Keywords
4.5 Review Questions
4.6 Further Readings

Objectives

After studying this unit, you will be able to:

z z Discuss the various types of wireless networks
z z Explain wireless PAN Technologies (WPAN)

Introduction

Wireless LAN (WLAN) is very popular nowadays. Maybe you have ever used some wireless
applications on your laptop or cellphone. Wireless LANs enable users to communicate without
the need of cable. Each WLAN network needs a wireless Access Point (AP) to transmit and
receive data from users. Unlike a wired network which operates at full-duplex (send and receive
at the same time), a wireless network operates at half-duplex so sometimes an AP is referred as
a Wireless Hub.
The major difference between wired LAN and WLAN is WLAN transmits data by radiating
energy waves, called radio waves, instead of transmitting electrical signals over a cable.WLAN
uses CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) instead of CSMA/
CD for media access. WLAN can’t use CSMA/CD as a sending device can’t transmit and receive
data at the same time.

Nowadays there are three organizations influencing WLAN standards. They are: ITU-R: which is
responsible for allocation of the RF bands , IEEE which specifies how RF is modulated to transfer
data and Wi-Fi Alliance that improves the interoperability of wireless products among vendors.
But the most popular type of wireless LAN today is based on the IEEE 802.11 standard, which is
known informally as Wi-Fi. The 802.11a operates in the 5.7 GHz ISM band. Maximum transmission
speed is 54Mbps and approximate wireless range is 25-75 feet indoors. 802.11b operates in the

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