This book gives a comprehensive overview of the technologies for the advances of
mobile radio access networks. The topics covered include linear transmitters,
superconducting filters and cryogenic radio frequency (RF) front head, radio over
fiber, software radio base stations, mobile terminal positioning, high speed
downlink packet access (HSDPA), multiple antenna systems such as smart
antennas and multiple input and multiple output (MIMO) systems, orthogonal
frequency division multiplexing (OFDM) systems, IP-based radio access networks
(RAN), autonomic networks, and ubiquitous networks.
OSCILLATORS are key building blocks in integrated transceivers. In wired and
wireless communication terminals, the receiver front-end selects, amplifies and
converts the desired high-frequency signal to baseband. At baseband the signal can
then be converted into the digital domain for further data processing and demodula-
tion. The transmitter front-end converts an analog baseband signal to a suitable high-
frequency signal that can be transmitted over the wired or wireless channel.
This book presents millimeter wave communication system design and analysis at the
level to produce an understanding of the interaction between a wireless system and its
front end so that the overall performance can be predicted. Gigabit wireless commu-
nications require a considerable amount of bandwidth, which can be supported by
millimeter waves. Millimeter wave technology has come of age, and at the time of
writing the standards of IEEE 802.15.3c, WiGig, Wireless HD TM , and the European
Computer Manufacturers Association have recently been finalized.
Use of multiple antennas at both ends of wireless links is the result of the
natural progression of more than four decades of evolution of adaptive
antenna technology. Recent advances have demonstrated that multiple-
input-multiple-output (MIMO) wireless systems can achieve impressive
increases in overall system performance.
The first practical examples of mobile communications were used in many countries like
the USA, the UK and Germany in military services, and played a significant role in the
First World War to transfer important information from the front to headquarters to take
further actions. Good and secure wireless communications were an important need for all
military services – army, navy and air force. In this respect, the Second World War was a big
experimental battlefield for the development and evolution of mobile radio. It was in the
interests of governments that after the Second World War the military investment should
be paid back by civilian use, and all western European countries started their so-called first
generation of mobile communication networks.
Wirelesscommunications,especiallyinitsmobileform,hasbroughtusthefreedomofmobility
andhaschangedthelifestylesofmodernpeople.Waitingatafixedlocationtoreceiveormakea
phone call, or sitting in front of a personal computer to send an e-mail or download a video
program, has become an old story. Nowadays it is commonplace for people to talk over a cell
phonewhilewalkingonthestreet,ortodownloadandwatchamoviewhiletravelingonatrain.
Thisisthebenefitmadeavailabletousbythesuccessfulevolutionofwirelesscommunications
over three generations, with the fourth generation being under way.
The PW2606B is a front-end over voltage and over current protection device. It achieves wide inputvoltage range from 2.5VDC to 40VDC. The over voltage threshold can be programmed externally orset to internal default setting. The low resistance of integrated power path nFET switch ensures betterperformance for battery charging system applications. It can deliver up to 1A current to satisfy thebattery supply system. It integrates the over-temperature protection shutdown and auto-recoverycircuit with hysteresis to protect against over current events
The PW2601 is a charger front-end integrated circuit designed to provide protection to Li-ionbatteries from failures of charging circuitry. The device monitors the input voltage, battery voltageand the charging current to make sure all three parameters are operated in normal range. Thedevice will switch off internal MOSFET to disconnect IN to OUT to protect load when any of inputvoltage, output current exceeds the threshold. The Over temperature protection (OTP) functionmonitors chip temperature to protect the device. The PW2601 also can protect the system’sbattery from being over charged by monitors the battery voltage continuously. The deviceoperates like a linear regulator, maintaining a 5.1V output with input voltages up to the input overvoltage threshold.The PW2601 is available in DFN-2x2-8L package. Standard products are Pb-free and Halogenfree
