Wireless
Networking in the Developing World Second Edition
A practical guide to
planning and building low-cost
telecommunications
infrastructure
Contents
Where to Begin 1
Purpose of this book .........................................................2
Fitting wireless into your existing network. .......................
3
Wireless networking protocols. ..........................................3
Question & Answer. ..........................................................
5
A Practical Introduction to Radio Physics 9
What is a wave?. .............................................................
9
Polarization ...................................................................13
The electromagnetic spectrum. ........................................
13
Bandwidth. .. 15
Frequencies and channels. ..............................................
15
Behavior of radio waves. ................................................
15
Line of sight. ..................................................................22
Power. .........24
Physics in the real world. ................................................26
Network Design 27
Designing the physical network. ......................................51
802.11 wireless networks. ...............................................54
Mesh networking with OLSR. ...........................................
56
Estimating capacity. ........................................................65
Traffic optimization. ........................................................79
Internet link optimization. ..............................................
89
More information. ...........................................................93
Antennas & Transmission Lines 95
Cables. ........ 95
Waveguides. ..................................................................
97
Connectors and adapters. ..............................................100
Antennas & radiation patterns. .....................................
102
Reflector theory. ...........................................................
114
Amplifiers. ...................................................................115
Practical antenna designs. .............................................116
Networking Hardware 135
Wired wireless. .............................................................135
Choosing wireless components. .....................................
137
Commercial vs. DIY solutions .........................................139
Building an access point from a PC. ...............................143
Security & Monitoring 157
Physical security. ..........................................................
158
Threats to the network. .................................................160
Authentication. .............................................................
162
Privacy. ..... 167
Network Monitoring. .....................................................
174
What is normal?. ..........................................................
203
Solar Power 211
Solar energy. ...............................................................211
Photovoltaic system components. ..................................
212
The solar panel. ............................................................
217
The battery. .................................................................222
The power charge regulator. .........................................
229
Converters. ..................................................................
231
Equipment or load. .......................................................
232
How to size your photovoltaic system. ...........................
238
Cost of a solar installation. ............................................246
Building an Outdoor Node 249
Waterproof enclosures. .................................................
249
Providing power. ...........................................................250
Mounting considerations. ..............................................
251
Safety. .......257
Aligning antennas on a long distance link. ....................258
Surge and lightning protection. .....................................263
Troubleshooting 267
Building your team. ......................................................
267
Proper troubleshooting technique. ................................
270
Common network problems ..........................................
271
Economic Sustainability 281
Create a Mission Statement. ..........................................
282
Evaluate the Demand for Potential Offerings. ................283
Establish Appropriate Incentives. ...................................284
Research the Regulatory Environment for Wireless. .......
286
Analyze the Competition. ..............................................
286
Determine Initial and Recurring Costs and Pricing. ........
287
Secure the Financing. ....................................................291
Evaluate the Strengths and Weaknesses of the Internal
Situation. ....... 293
Putting it All Together. ..................................................
294
Conclusion. ..................................................................
297
Case Studies 299
General advice. .............................................................299
Case study: Crossing the divide with a simple bridge in
Timbuktu. ..... 302
Case study: Finding solid ground in Gao. .......................305
Case Study: Fantsuam Foundation's Community Wireless
Network. ...308
Case study: The quest for affordable Internet in rural Mali. .. 319
Case study: Commercial deployments in East Africa. ......325
Case study: Dharamsala Community Wireless Mesh Network.
............332
Case study: Networking Mérida State. ...........................
334
Case study: Chilesincables.org. ......................................345
Case study: Long Distance 802.11. .................................355
Appendix A: Resources 371
Appendix B: Channel Allocations 379
Appendix C: Path Loss 381
Appendix D: Cable Sizes 382
Appendix E: Solar Dimensioning 383
