SOLUTIONS MANUAL WIRELESS COMMUNICATIONS AND NETWORKS SECOND EDITION

WIRELESS COMMUNICATIONS AND NETWORKS SECOND EDITION WILLIAM STALLINGS Copyright 2005: William Stallings-2- © 2005 by William Stallings All rights reserved. No part of this document may be reproduced, in any form or by any means, or posted on the Internet, without permission in writing from the author.-3- NOTICE This manual contains solutions to all of the review questions and homework problems in Wireless Communications and Networks, Second Edition. If you spot an error in a solution or in the wording of a problem, I would greatly appreciate it if you would forward the information via email to me at . An errata sheet for this manual, if needed, is available at ftp:// W.S.-4- TABLE OF CONTENTS Chapter 2: Transmission Fundamentals.......................................................................5 Chapter 3: Communication Networks .........................................................................8 Chapter 4: Protocols and the TCP/IP Suite...............................................................14 Chapter 5: Antennas and Propagation.......................................................................17 Chapter 6: Signal Encoding Techniques ....................................................................22 Chapter 7: Spread Spectrum ........................................................................................28 Chapter 8: Coding and Error Control.........................................................................34 Chapter 9: Satellite Communications .........................................................................44 Chapter 10: Cellular Wireless Networks......................................................................48 Chapter 11: Cordless Systems and Wireless Local Loop...........................................54 Chapter 12: Mobile IP and Wireless Access Protocol.................................................56 Chapter 13: Wireless LAN Technology........................................................................59 Chapter 14: Wi-Fi and the IEEE 802.11 Wireless LAN Standard..............................61 Chapter 15: Bluetooth and IEEE 802.15........................................................................65-5- A NSWERS TO Q U E S T I O N S 2.1 A continuous or analog signal is one in which the signal intensity varies in a smooth fashion over time while a discrete or digital signal is one in which the signal intensity maintains one of a finite number of constant levels for some period of time and then changes to another constant level. 2.2 Amplitude, frequency, and phase are three important characteristics of a periodic signal. 2.3 2π radians. 2.4 The relationship is λf = v, where λ is the wavelength, f is the frequency, and v is the speed at which the signal is traveling. 2.5 The spectrum of a signal consists of the frequencies it contains; the bandwidth of a signal is the width of the spectrum. 2.6 Attenuation is the gradual weakening of a signal over distance. 2.7 The rate at which data can be transmitted over a given communication path, or channel, under given conditions, is referred to as the channel capacity. 2.8 Bandwidth, noise, and error rate affect channel capacity. 2.9 With guided media, the electromagnetic waves are guided along an enclosed physical path, whereas unguided media provide a means for transmitting electromagnetic waves through space, air, or water, but do not guide them. 2.10 Point-to-point microwave transmission has a high data rate and less attenuation than twisted pair or coaxial cable. It is affected by rainfall, however, especially above 10 GHz. It is also requires line of sight and is subject to interference from other microwave transmission, which can be intense in some places. 2.11 Direct broadcast transmission is a technique in which satellite video signals are transmitted directly to the home for continuous operation. 2.12 A satellite must use different uplink and downlink frequencies for continuous operation in order to avoid interference. 2.13 Broadcast is omnidirectional, does not require dish shaped antennas, and the antennas do not have to be rigidly mounted in precise alignment. 2.14 Multiplexing is cost-effective because the higher the data rate, the more cost-effective the transmission facility.