Electronic Design

Ultra Wideband Systems: Technologies and Applications

Edited by Robert Aiello and Anuj Batra<br>ISBN: 0750678933

Books on ultra wideband UWB have been pretty scarce. This technology only just emerged from secrecy and obscurity in the late 1990s, and reference works are rare. This once highly classified technology has come out of the closet so to speak, but it has only been recently that some practical books have become available. I say practical meaning books the working engineer can use to design and build real systems without having to get a doctorate in EE. This is just such a book. With a copyright date of 2006, it is pretty current with technology, standards, and applications.

This is also one of those books that is written by multiple authors, typically one chapter per author. The authors are experts in their own areas of UWB so you are getting the real scoop on each topic. The editors work at UWB companies Staccato Communications and Texas Instruments respectively, so they too know what they are doing.

Chapter 1 is the history of UWB. I would say it is incomplete as it leaves out lots of the early days as well as many of the companies that played an early role in UWB. So let's just be kind here and say it is an accurate "recent" history of the technology. You don't have to know squat about the history to use UWB anyway, but some of you want to know the gory details about where somethings come from.

Chapter 2 covers the spectrum and regulations. A great summary of the agony of getting the FCC to bless UWB. UWB must comply with the FCC Parts 2 and 15 of Title 47 of the code of federal regulations (CFR). They are about as strict as most of us have ever seen. Since UWB is allowed to operate in the 3.1- to 10.6-GHz range, it will typically overlay lots of other wireless services. So power level and other EMI related specs are supposed to minimize interference. This chapter is must reading for anyone getting ready to deploy UWB.

Chapter 3 introduces to the interference and coexistence issues that surround UWB. Again, must reading if you are ever going to get your UWB design approved by the FCC.

Chapter 4 is a beauty covering UWB antennas. Most other UWB books omit this critical subject. Since UWB is so broadband and antennas are so inherently resonant and narrow band, you have to wonder how to make an effective UWB antenna. This chapter tells how. All the appropriate math is there but also lots of practical advice about how to create an efficient UWB antenna.

Chapter 5 gets to the heart of how UWB works. This chapter describes the traditional impulse type of UWB which was what the original UWB researchers invented. Also known as impulse radio and direct sequence UWB, you see how the pulses are coded. You get all the different codes and how to use them. What I didn't see was anything that tells you how to make the pulses or how they translate to a given bandwidth. A serious omission in my opinion. But the material there on codes is very good. The most accepted direct sequence (DS) UWB standard is described in detail.

Chapter 6 addresses multiband approach to UWB. This is a system where data is transmitted with different symbols in different frequency bands in a periodic sequence. I have not seen this implemented in an IC yet but who knows. It may have its uses. Good background material and a possible solution to your needs.

Chapter 7 introduces you to spectral keying, a type of modulation scheme for UWB. This was a new one on me, but it has its supporters. Most wireless engineers do not know this exists, but this is a good chance to learn about another option you have.

Chapter 8 covers the most popular version of UWB called multiband UWB. In the opinion of many, MB-UWB is not real UWB because it is not the impulse type. Instead, it is just a really wideband implementation of OFDM. This format has become the de facto standard and it is what most of the UWB chip and module companies make. This chapter is a great intro to the nitty gritty details for this system.

Chapter 9 covers the media access control (MAC) designs for UWB radios. This is a topic rarely discussed outside the IEEE and other standards committees. It is a pretty good look at how the data is handled at the higher layer of the OSI model.

Chapter 10 covers the standards. UWB was supposed to be standardized by the IEEE but it never made it. Squabbling and dissent between the DS-UWB and MB-UWB camps lead to a stalemate so the EEE 802.15.3a standard was never completed. This chapter tells that story but it does not have the ending since that battle wasn't over when the book was completed. Good reading nevertheless and a real look at how standards are made, or not made, as in this case.

Chapter 11 covers applications. It does a good job of covering video, audio and other media transmission. Fast wireless USB with UWB is covered. Amazingly, radar is never mentioned. UWB was originally developed for secure data transmission and radar. Today, the primary working UWB systems are ground penetrating radars (GPR) which are used by public utilities to look for below surface flaws in roads and bridges and by police and military who use it to see through walls and predict the presence of bad guys. A major omission in my opinion.

Despite the few gripes I mentioned above, this is a pretty good book and I am glad to have it on my reference shelf.

If you're interested in ultra wideband (UWB) technology, you might also like these books:

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