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Review: Space-Time Block Coding for Wireless Communications December 19, 2010

Posted by flashbuzzer in Research.
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I recently finished Space-Time Block Coding for Wireless Communications by E.G. Larsson and P. Stoica. I originally used this book for a course taught by my advisor in the Fall 2005 semester.

This book only has one review on Amazon, so I hope that my thoughts will be useful for people who are considering obtaining the book.

In this book, the authors introduce the fundamental concepts of multi-input multi-output (MIMO) wireless communications and space-time block coding (STBC), and they show how STBC can significantly improve the performance of MIMO systems in many ways. They begin by presenting the tools that are necessary for a thorough understanding of MIMO systems, including channel modeling, information theory and error probability analysis. They then recap the familiar concept of receive diversity and use it to motivate the breakthrough concept of transmit diversity, which leads to the introduction of STBC. The rest of the book is a compendium of advanced topics for STBC, including coding for ISI channels, the design of coherent/non-coherent STBC receivers, coding for transmitters with partial/full CSI, and coding in the presence of interference.

The authors do a fantastic job of presenting and teaching fundamental concepts to the reader. A painstaking amount of effort is made to hammer home key points and build the right level of intuition. In particular, the authors set the tone for the remainder of the book in Chapter 1 by presenting a simple example that considers 2×1 and 1×2 systems; moreover, the book contains numerous examples of systems that employ one or two transmit/receive antennas, which is invaluable in terms of enhancing the learning process. The book is also well-organized; to wit, the authors present several theorems and results in Chapters 4 (“Error Probability Analysis”) and 7 (“Linear STBC for Flat Fading Channels”). By constantly referring to results in these two chapters, it is clear that they are meant to serve as a focal point for understanding the rest of the book. In addition, the authors have put a great deal of effort into generating performance plots; they are properly labeled, and the various curves in each plot are easy to distinguish.

It should be noted that the authors engage in some degree of self-promotion in the book, especially in the latter chapters (9-11); in my view, this detracts (albeit slightly) from its quality. Now it should also be noted that such self-promotion is difficult to avoid, especially when discussing a (relatively) nascent research area in which the authors have obtained many of the major results. A more balanced approach to describing these concepts would have been in order, though. In particular, the authors should have more fully elucidated the drawbacks of using OSTBC in MIMO systems, in order to not perpetuate the impression that OSTBC are the “best choice” in terms of transmit-side strategies. Also, the book has only four errata listed on this page, though I am quite certain that the book has more than four errata. In addition, the book relies heavily on a thorough understanding of matrix analysis; at this point I’m not aware of a good textbook on that topic, though. For those who would cite the text by Horn and Johnson, my thought is that it is more of a reference book than an actual teaching tool.

Overall I would strongly recommend this book to those who want to gain a more solid understanding of MIMO systems and the role that STBC can play in terms of improving their performance.


Review: Introduction to Space-Time Wireless Communications January 25, 2010

Posted by flashbuzzer in Research.
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I recently finished Introduction to Space-Time Wireless Communications by A. Paulraj, R. Nabar and D. Gore. I originally used this book for a course taught by my advisor in the Fall 2005 semester. On a (possibly) related note, savvy Internet denizens will discover that Paulraj is my “academic grandfather.”

This book has already been reviewed (some would say “thoroughly castigated”) on Amazon, so I’ll just contribute some of my observations and hope that they provide some additional data points for people who are considering obtaining the book.

I had a conversation regarding this book with one of my former research group-mates that proved to be enlightening. He encouraged me to re-read the preface, where the authors state, “this area of technology has grown so large in the past few years that this book cannot cover all aspects in moderate detail. Rather, our aim has been to provide a coherent overview of the key advances in this field emphasizing basic theory and intuition. We have attempted to keep the presentation as simple as possible without sacrificing accuracy.”

When I viewed the book in this light, I was able to tolerate the first eight chapters, which appear to be (mostly) presented at the stated level of detail. In those first eight chapters, the authors do a reasonable job of presenting (without much in the way of rigorous proofs, as expected) fundamental concepts including space-time channel modeling, space-time channel capacity and space-time coding. They even cover a somewhat advanced topic, transmit-side precoding, at a reasonable level.

In my opinion, the book really “goes off the rails” in the last four chapters, which make a half-hearted attempt at presenting more advanced topics including MIMO-OFDM, the MIMO MAC/BC channels and the (much celebrated) diversity-multiplexing tradeoff. Unfortunately, this degrades the cohesion of the book and even left me with a sour taste in my mouth as I finished the last section. Various results were presented without even a modicum of intuition or insight, including the entire chapter on space-time co-channel interference mitigation, which suffered from lazy and uninspired writing (note that interference is a critical issue in multi-antenna wireless networks).

Overall, I would recommend this book to “graduate students in wireless communications” and “wireless designers in industry” (as noted in the text) with the following caveats. Readers would be advised to focus only on the first eight chapters and become familiar with their basic results. After achieving this goal, they should employ a variety of methods to gain deep intuition and insight on all of the material in the text, including reading through the relevant references, attempting to re-derive the key results, and discussing them with motivated colleagues. For example, I should note that I acquired a much better understanding of the diversity-multiplexing tradeoff after an extensive whiteboard-aided discussion with one of my former research group-mates.

Perhaps a more hard-hitting (and well-written) book on space-time wireless communications is in the works (heh heh).