Implementing 802.11, 802.16 and 802.20 wireless networks: planning, troubleshooting, and maintenance

255 Pages·2004·3.958 MB·English

by  Ron Olexa

Implementing 802.11, 802.16,
and 802.20 Wireless Networks
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Implementing 802.11, 802.16,
and 802.20 Wireless Networks
Planning, Troubleshooting and Operations
by Ron Olexa
AMSTERDAM • BOSTON • HEIDELBERG • LONDON
NEW YORK • OXFORD • PARIS • SAN DIEGO
SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO
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Contents
Preface ........................................................................................ix
Introduction ...............................................................................xiii
What’s on the CD-ROM? ............................................................ xix
Chapter 1: High-Speed Wireless Data: System Types,
Standards-Based and Proprietary Solutions ............................3
Fixed Networks ............................................................................................4
Nomadic Networks ......................................................................................5
Mobile Networks .........................................................................................6
Standards-Based Solutions and Proprietary Solutions .................................6
Overview of the IEEE 802.11 Standard .......................................................7
Overview of the IEEE 802.16 Standard .....................................................14
10−66 GHz Technical Standards ...............................................................16
2−11 GHz Standards ..................................................................................16
Overview of the IEEE 802.20 Standard .....................................................17
Proprietary Solutions .................................................................................18
Chapter 2: Basic Radio and RF Concepts .......................................27
RF Energy ..................................................................................................27
RF Generation and Transmission ...............................................................30
Oscillator ....................................................................................................30
Power Amplifiers .......................................................................................34
Antennas and Feedlines .............................................................................35
RF Reception .............................................................................................41
Modulation of RF Signals ..........................................................................44
Amplitude Modulation ...............................................................................44
Frequency Modulation ...............................................................................46
Complex Modulation .................................................................................47
Duplexing ...................................................................................................54
v
Contents
Frequency Division Duplexing ..................................................................54
Time Division Duplexing ...........................................................................55
Multiple Access Techniques .......................................................................55
Spread-Spectrum Modulation ....................................................................58
OFDM ........................................................................................................62
Ultra Wideband ..........................................................................................64
Chapter 3: Propagation, Path Loss, Fading and Link Budgets ..........69
Path Loss and System Coverage ................................................................79
Frequency Reuse ........................................................................................85
Chapter 4: Propagation Modeling and Measuring ...........................95
Predictive Modeling Tools .........................................................................95
Spreadsheet Models ...................................................................................96
Terrain-Based Models ................................................................................97
Effectively Using a Propagation Analysis Program ...................................98
Using a Predictive Model .........................................................................104
The Comprehensive Site Survey Process .................................................106
Survey Activity Outline ...........................................................................110
Identification of Requirements .................................................................112
Identification of Equipment Requirements ..............................................113
The Physical Site Survey .........................................................................114
Determination of Antenna Locations .......................................................115
RF Site Survey Tools ...............................................................................117
The Site Survey Checklist ........................................................................119
The RF Survey .........................................................................................120
Data Analysis ...........................................................................................123
Chapter 5: System Planning .......................................................131
System Design Overview .........................................................................131
Location and Real Estate Considerations ................................................132
System Selection Based Upon User Needs ..............................................139
Identification of Equipment Requirements ..............................................140
Identification of Equipment Locations .....................................................143
Channel Allocation, Signal-to-Interference, and Reuse Planning ...........151
Network Interconnect and Point-to-Point Radio Solutions .....................155
vi
Contents
Costs .........................................................................................................159
The Five C’s of System Planning .............................................................159
Chapter 6: System Implementation, Testing
and Optimization ............................................................163
Real-World Design Examples ..................................................................163
Example One: Local Coffee House .........................................................163
Example Two: Office LAN Deployment .................................................165
2.4 GHz RF Coverage Results .................................................................169
5.6 GHz RF Coverage Results .................................................................170
Capacity Requirements ............................................................................171
System Design Analysis ...........................................................................171
NEC, Fire, and Safety Code Concerns .....................................................174
Example Three: Community WISP .........................................................176
Community: A Garden Style Apartment Complex ..................................177
RF Considerations ....................................................................................178
Backhaul ..................................................................................................181
Weatherproofing .......................................................................................183
Grounding and Lightning Protection .......................................................184
Community: A Small Area Subdivision ...................................................185
Equipment Selection ................................................................................185
System Planning ......................................................................................187
Community: An Urban or Suburban Area Serving Business Users .........188
Spectrum Issues .......................................................................................188
Design Considerations .............................................................................190
Community: A Small Town System for Consumer and Business Users .191
Summary ..................................................................................................191
Example Four: Mobile Broadband Network ............................................192
Initial Modeling .......................................................................................192
Preliminary Information ...........................................................................193
Coverage Modeling ..................................................................................194
Capacity Modeling ...................................................................................194
Cost Modeling ..........................................................................................195
Designing in the Real World ....................................................................195
Chapter Summary ....................................................................................197
vii
Contents
Chapter 7: Back Office System Requirements ...............................201
Network Systems Required ......................................................................201
Customer Authorization System ..............................................................202
Billing Data Collection ............................................................................203
Network Monitoring and Control ............................................................203
Billing System ..........................................................................................204
Trouble Ticketing .....................................................................................205
Customer Service Systems .......................................................................206
Design Considerations and Requirements ...............................................208
Chapter 8: Network Performance Testing and Troubleshooting ......213
Low RSSI and Noise Levels in a Single Area ..........................................215
High Noise or Interference Levels ...........................................................216
Throughput Problems Unrelated to Signal or Noise ................................218
Repeater Mode ........................................................................................219
Multiple Channel Reuse in a Close Area .................................................220
Near/Far Problems ...................................................................................220
Hidden Node Problems ............................................................................220
Client Card “Roam” .................................................................................221
Viruses and Trojans ..................................................................................221
Troubleshooting Summary .......................................................................222
About the Author .....................................................................223
List of Acronyms .......................................................................225
Index .....................................................................................229
viii
Preface
Communication, a word that many associate with modern technology, actually
has nothing to do with technology. At its core, communication involves nothing
more than the spoken or written word, and symbolic languages like art and music.
Technology has become synonymous with communication because technology
has historically been the method by which communication to or by the general
population takes place. From the printing press to the telephone to radio and TV
broadcasting, technology has touched our lives by providing convenient ways for
a large population to communicate. Because the intertwining of technology and
communication is fundamental to our culture, the technology of communication
in a way defines our culture.
As we enter the early years of the 21st century, humanity is awash in instant com-
munication based upon the radio technology that makes it possible. As a society
we have near real time access to world events occurring in any corner of the
globe, and as individuals we have instant voice communication with each other by
virtue of the telephone in its many shapes and forms.
Over the last decade of the 20th century, the cell phone redefined our cultural
expectations of communication. The advent of the portable phone along with price
competition among hardware and service providers has brought true personal
voice communication service to a large segment of humanity.
But what of symbolic communication? Computing power and flexibility have
allowed us to digitize these communications to make their dissemination more
convenient, and the portable phone has set an expectation that all communica-
tion requires portability, convenience, and cost effectivity. Unfortunately, these
voice-centric systems have only marginally addressed the more complex nature
of symbolic communications. Moreover, as a society we are no longer content
with simplistic communication. The advent and adoption of the computer and the
myriad software packages available for it has offered the ability to generate a new
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