Customer Reviews

Fundamentals of WiMAX: Understanding Broadband Wireless Networking

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I was looking for a book on WiMax as a reference for designing WiMax radios. Trying to understand WiMax by reading the IEEE 802.16, 16e standards is difficult. The original 802.16-2004 standard was organized in a convoluted way. On top of that there were numerous errors, even in the mathematical formula and the critical system parameters. 16e was written as a errata and addendum to .16. Given the amount of major changes required by .16e, this format of a .16+.16e makes it almost impossible to read to gain engineering understanding. I was looking for a book that could untangle this mess and present the information in .16+.16e in a linear and logical way, if not the MAC, at least the PHYs. The Andrews book does not serve this purpose. Most of the technical details of the WiMax system are missing. For example, a WiMax radio starts with transmitting or receiving the preambles. There are hundreds of preambles in WiMax. I would expect the book to describe all these preambles for reference. It would be even better, if there are insights into the mathematical properties of these preambles for the receiver design. If you agree with my statement, just let me say that the Andrews book contains none of the details the preambles beyond saying WiMax has something called preamble. Of the limited amount of PHY details the book did contain, there are critical errors. For example, the book seems to suggest that the downlink PUSC subchannels consist of two chunks of contiguous OFDM subcarriers of 14 each. According to the 802.16/16e, the 28 subcarriers in a subchannel are scattered. For the lack of details, I feel this book serves poorly as an engineering design reference. It also serves poorly as a guide to untangle the material in IEE802.16/16e due to the lack of details and the critical errors.

As of May 28 2007, if you are going to fork some money onto a WiMax book, this book should be it. The authors were smart to concentrate in explaining the technology building blocks of the standard instead of just following the structure of the 802.16 document. I have read mostly the chapters related to the PHY and I found the explanations and examples clear and to the point. Even if you are not interested in the WiMax standard per se, this book contains very good information about OFDM/OFDMA and multi-antenna techniques for broadband wireless systems. It also has a couple of chapters about link level and system level performance of WiMax that add even more depth to the book.

Andrews suggests in the Preface that the book will be suited to a wide range of people who want to learn about WiMax. From engineers to graduate students to managers and executives and others. Indeed, there are high level descriptions, scattered throughout the chapters, accessible to those without an engineering degree. But typically, these are introductory summary remarks. The bulk of every chapter is really best understood if you have that engineering background. While the author naturally desires as wide an audience as possible, this is really an engineer's book.

The overviews do show that WiMax exhibits strong advantages over the current and popular WiFi. Like having robust security protocols, including the Advanced Encryption Standard (aka Rijndael) and 3DES. Plus WiMax has terminals that possess built-in digital certificates with public and private keys and MAC addresses. Contrast this with WiFi, whose commonly used Wireless Encryption Protocol has some severe deficiencies.

Another important advantage of WiMax is how it supports extreme mobility modalities. Where you, the end user, can travel in a vehicle up to 120 kmph, and have seamless handoff between WiMax basestations.

Many chapters are highly mathematical. Indeed, one chapter on multi-antennas reads like an excursion into advanced linear algebra or matrix theory. It even evokes the Frobenius norm of a matrix, which I'd only ever seen before in a pure maths course.

Of all the chapters, maybe that which discusses Mobile IP could be the most interesting. It takes the Internet as we know it, and removes a serious current limitation to moving your machine, and having it keep connected to the Internet. Mobile IP is a cunning overlay on IPv4. While it can also be done, and much easier, in IPv6. The only problem is when the latter will start to dominate v4.

Overall, the book is a very promising pitch for WiMax deployment.

I think this book gives you a little bit more that just the fundamentals of WiMax. You should read this book only if you have a decent understadings in communication theory because. If you do the topics covered in this book will make a lot more sense, otherwise you will be struggling with a lot of the concepts and acronyms.

Enjoyed the earlier chapters and how they introduced the later chapters which went into greater detail on each topic. The detailed chapters included equations, tradeoffs and examples.

This is an excellent starter book on WiMAX. The most useful aspect of this book is the extensive coverage of IEEE 802.16e (mobile WiMAX) PHY and MAC standards. Another very useful feature is the listing of typical system configurations used in real deployments of WiMAX. The technical chapters on OFDM, OFDMA, and space-time coding are also useful but can be found in other texts.

For those looking for an overview of IEEE 802.16 technology, or for those looking to come up to speed after a period of absence such as me, this is a good book.