A decade ago, I first wrote that people moved, and networks needed to adapt to the
reality that people worked on the go. Of course, in those days, wireless LANs came
with a trade-off. Yes, you could use them while moving, but you had to trade a great
deal of throughPUT to get the mobility. Although it was possible to get bits anywhere,
even while in motion, those bits came slower. As one of the network engineers I worked
with PUT it, “We’ve installed switched gigabit Ethernet everywhere on campus, so I
don’t understand why you’d want to go back to what is a 25-megabit hub.” He un-
derestimated the allure of working on the go.
This book was born from the perception that there is much more to spectrum use
and sharing than one sees reflected in publications, whether academic, commercial
or political. the former – in good research style – tend towards reductionism and
concentrate on specific, detailed aspects. commercial publications tend to empha-
size the positive aspects and they tend to PUT promise above practice. Given the ever
increasing pace of technology development and recent successes of new wireless
technologies, some pundits predict large-scale spectrum scarcity, potentially lead-
ing to economic catastrophe. Although economic theory has a hard time explaining
recent events that shook the world economy, the notion of spectrum scarcity is intui-
tively acceptable, even if not correct or immediately relevant.
The ability to analyze system or circuit behavior is one of the key requirements for
successful design. To PUT an idea to work, a designer needs both the knowledge
and tools for analyzing the behavior of that new system architecture or that experi-
mental circuit topology. Design decisions are grounded on the results obtained from
analysis.
Each of us is interested in optimization, and telecommunications. Via several meetings,
conferences, chats, and other opportunities, we have discovered these joint interests and
decided to PUT together this book.
The explosion in demand for wireless services experienced over the past 20 years
has PUT significant pressure on system designers to increase the capacity of the
systems being deployed. While the spectral resource is very scarce and practically
exhausted, the biggest possibilities are predicted to be in the areas of spectral reuse
by unlicensed users or in exploiting the spatial dimension of the wireless channels.
The former approach is now under intense development and is known as the cogni-
tive radio approach (Haykin 2005).
As a student I did my best to avoid text books – a strange statement for a Professor to make and one that
I should clarify before you PUT this book down; I did my best to avoid text books that did not help me.
The Raspberry Pi has become a comPUTing phenomenon. This single-board miniature
comPUTer, first released in February 2012 by the Raspberry Pi Foundation, has grown into
a series of nearly a dozen models that have sold a total of more than 10 million units in
five years.
Inexpensive to buy and to run, Raspberry Pi comPUTers are great for enthusiasts,
good for games, and fun for children. Raspberry Pi comPUTers are also terrific in the
classroom, enabling you to PUT on each desk an easily-manageable comPUTer on which
students can do everything from learning Internet use and essential office software skills,
through grasping programming basics in an easy-to-learn format, to performing full-on
programming in Python, Java, C, and other languages. Better yet, you can install all the
software needed for those activities automatically alongside the operating system.
The PW4055 is a complete constant-current /constant-voltage linear charger for single cell lithiumion batteries.Its ThinSOT package and low external component count make the PW4055 ideallysuited for portable applications.Furthermore, the PW4055 is specifically designed to work within USBpower specifications.The PW4055 No external sense resistor is needed, and no blocking diode is required due to theinternal MOSFET architecture.Thermal feedback regulates the charge current to limit the dietemperature during high power operation or high ambient temperature. The charge voltage is fixedat 4.2V, and the charge current can be programmed externally with a single resistor. The PW4055automatically terminates the charge cycle when the charge current drops to 1/10th the programmedvalue after the final float voltage is reached. When the inPUT supply (wall adapter or USB supply) isremoved, the PW4055 automatically enters a low current state, dropping the battery drain currentto less than 2μA. The PW4055 can be PUT into shutdown mode, reducing the supply current to 25μA.The BAT pin has a 7KV ESD(HBM) capability. Other features include charge current monitor, undervoltage lockout, automatic recharge and a status pin to indicate charge termination and the presenceof an inPUT voltage
