The Essential Guide to Wireless Communications Applications, Second Edition: From Cellular Systems to Wi-Fi

• Authors: Andrew Dornan
• Venue: The Essential Guide to Wireless Communications Applications, Second Edition: From Cellular Systems to Wi-Fi
• Year: 2002

From the Book:PrefaceThe first cell phone I ever saw was the size of a small television set. It needed an antenna to match, and a battery that now would look more at home in a car. While this could theoretically last ten hours between charges, actually making calls reduced its lifetime to minutes. The cellular network itself was equally primitive, with coverage so poor that I often had to lean out of a window in order to pick up a signal.The whole system was so unreliable that mobile phones often seemed more like expensive toys than a serious means of communication, and indeed they were often sold as such. Their high cost-a minute's talk time cost around an hour's salary-made them popular status symbols. People would clip phones to their belts as a way to show off how rich and important they were (or believed themselves to be).I'd bought mine for the opposite reason: My crumbling flat in Notting Hill wasn't able to support a landline, and I reasoned that even an expensive and erratic connection was better than nothing. When the building eventually caught fire, I wasted valuable seconds giving directions to the emergency services operator: Mobile phones aren't mapped to addresses in the same way as landlines, so as far as she knew, I could have been anywhere in the country.A decade later, I again had to make an emergency call from a mobile phone. This time, the emergency operator was able to determine which part of San Francisco I was in, thanks to equipment that automatically relayed the location of the cellular base station I was closest to. Had I been in Tokyo, it would have been able to do even more, pinpointing my exact latitude and longitude. Such systemsare on their way to other parts of the world, prompted both by regulations designed to enhance public safety and by a commercial imperative to offer location-based services. They also raise obvious privacy and security fears, as do several other aspects of wireless networking.What's New The ability to pinpoint a location to within a few meters is just one of the new technologies that have emerged since the first edition of this book. Though it was published only two years ago, wireless is such a fast-moving industry that a lot has changed in this time.The idea that people who have telephone wires leading to their homes will willingly rely on a mobile as their primary phone no longer seems absurd. Nor does the idea of surfing the Web while sitting under a tree, or watching TV streamed across the Internet from the other side of the world while riding a bus. As a result, I have totally rewritten much of this book, adding new sections and figures to every chapter.Other new developments since the first edition include Ultra Wideband, which is still in its infancy but may soon allow very high-speed data transmission over short distances, and T-Rays, a type of link that mixes the qualities of light with those of radio. The most significant is the growth of wireless Local Area Networks (LANs), which now appear to be playing a greater role in the wireless future than many had once thought. Amidst the dotcom and telecom busts of 2001, Wi-Fi (IEEE 802.11b) was a great success story. Its successor could even form the basis of fourth-generation systems, which unlike so much else in the wireless world might actually arrive ahead of schedule.For computer geeks like me, this a welcome change. A wireless LAN is something that individual people can set up and tinker with at relatively low cost, not a service provided by a giant corporation and licensed by the government. Of course, most people don't want to construct their own networks, so the technology still has a way to go. I've tried to look at how it will develop, as well as explain the competing standards and what each can do.Not every change in those two years has been positive for the wireless industry: Though technology advanced, the economy collapsed, and many companies that planned or built wireless networks have fallen into bankruptcy. (I particularly miss Metricom and its Ricochet system.) New sections in Chapters 1 and 7 deal with the realities of the wireless business, which is actually surprisingly resistant to wider economic recession and even depression.As well as all these revisions, there is one new chapter, examining the possible health risks of wireless communications. Though radiation from a cell phone is unlikely to be the "new smoking" as some alarmists claim, mounting evidence since the first edition suggests that it is not entirely risk-free. I personally have not decided to limit my use of cell phones and wireless data devices, but then I also drink beer and ride a bicycle without a helmet (though not at the same time). You may reach a different conclusion. Wireless devices also bring about other safety and social problems: Regardless of any effects from radiation, it's now clear that using a cell phone while driving can kill.About This Book Most of us form some kind of picture in our mind when we talk to someone on the phone. We usually still imagine them sitting at a desk or lounging on a sofa, but those pictures are no longer true. Dial a number in some European countries, and the chances are that it will reach a wireless phone. The person you talk to could be sailing in Lake Geneva, trekking across Lapland, or just walking down any city street.Soon we won't have to imagine. The phone companies are already demonstrating wireless videophones that double as pen-based computers-and that's just the start. The very term cell "phone" is itself becoming outdated, as the latest mobile data terminals are already able to more than just transmit voice. Visionaries predict mobile links as good as those that office computer users enjoy, enabling high-speed Internet access, responsive networked applications, and crystal-clear video.Even more exciting are the new applications unique to mobile devices: location-based maps, personalized weather forecasts, even real-time medical monitoring. Electronic currency could allow a cell phone to become a virtual wallet, transmitting the equivalent of cash to stores both in the real world and online. Marketers refer to all these applications as the "wireless Web," a somewhat empty phrase. It is both as meaningless and as promising as the "Information Superhighway" of nearly a decade ago.The Essential Guide to Wireless Communications Applications is designed to look beyond the hype, examining just what is and isn't possible with present-day and future wireless systems. It is primarily focused on the applications, but a proper understanding of these requires a look at the underlying technology. For example, the first version of WAP promoted a backlash among European users because it had been promoted as equivalent to the wired Internet. If the PR people had understood the technology and been more honest, it might have seemed less of a disappointment.This book is intended for anyone who wants (or needs) to learn about the new wave of wireless networks. It will introduce you to all the most important wireless technologies, then explore their likely impact on both commerce and culture.Structure Each chapter is intended to stand alone, though the whole book should also make sense when read from beginning to end. Readers who already know a bit about the technology, or who are entirely technophobic, may wish to skip some parts of Chapters 2 to 5. These explain in detail how the first, second, third, and now fourth generations of cellular systems work, including the type of applications that each is best suited to as well as the financial and regulatory problems in their way.Chapters 6 and 7 focus solely on the applications, looking at the types of services available from each system today and tomorrow. They also take a look at the hard economics behind investment in mobile systems, and the reason that Europe's telecom carriers have gambled around a trillion dollars on new spectrum licenses and equipment.The hardware required by a wireless network is surveyed in Chapter 8, from the cellular operators' infrastructure of radio masts to the servers hosting individual WAP and i-mode sites. Chapter 10 investigates mobile phones themselves, considering the different paths that their evolution may take. Some pundits predicting that they will expand to become computers, others that they will shrink to the size of headsets.As mentioned above, wireless LANs are among the most interesting new mobile technologies, as well as the fastest changing. Chapter 9 takes a detailed look at these, as well as similar systems such as Bluetooth and cordless phones. This is the longest chapter in the book, as well as the one that has changed the most from the first edition.While terrestrial mobile technologies receive most of the hype, fixed wireless and satellite technologies are also interesting. Chapters 11 and 12 look at these. With fiber and Digital Subscriber Line (DSL) looking less attractive all the time, satellite and fixed wireless could be the best hope that most residential customers have for high-speed Internet access. Satellite networks are particularly exciting, and despite many high-profile failures, new satellite constellations are always on the launch pad. They claim to offer truly global networks, promising access from ocean liners, intercontinental jets, and even the South Pole.At the end of every chapter is a summary page, highlighting the important information contained within. Each chapter also contains a short a list of relevant Web sites, for readers wanting to learn more. None of these have any connection with this book, but all contain some useful information. There's always a risk that Web sites will change or disappear—one that was listed in the first edition has since been replaced with a hardcore porn site—so I have also added a more conventional bibliography, listing other relevant dead tree books.