During the past years, there has been a quickly rising interest in radio access tech-
nologies for providing mobile as well as nomadic and fixed services for voice,
video, and data. The difference in design, implementation, and use between
telecom and datacom technologies is also getting more blurred. One example is
cellular technologies from the telecom world being used for broadband data and
wireless LAN from the datacom world being used for voice over IP.
In 2005, when the world crossed-over to Web 2.0, business professionals and managers in
every industry – from traditional retail to high tech media and telecom – felt the first powerful
tremors of the strategic shifts taking place, sweeping away traditional business models and
altering competitive landscapes.
Optical communication technology has been extensively developed over the
last 50 years, since the proposed idea by Kao and Hockham [1]. However, only
during the last 15 years have the concepts of communication foundation, that
is, the modulation and demodulation techniques, been applied. This is pos-
sible due to processing signals using real and imaginary components in the
baseband in the digital domain. The baseband signals can be recovered from
the optical passband region using polarization and phase diversity tech-
niques, as well as technology that was developed in the mid-1980s.
LTE-Advanced becomes a truly global standard for 4G cellular communications.
Relay, as one of the key technologies of LTE-Advanced, can significantly extend
the coverage, and improve the system throughput. LTE-A standards and tech-
nologies were described in several recent books where the limited pages for relay
feature prevent the detailed explanations of the technology. In this book, we tried
to provide an in-depth description of LTE-A relay development. More specifically,
significant portions are spent on relay channel modeling and potential technologies
during the study item phase of the development, although some of those tech-
nologies, such as Type 2 cooperative relay, multi-hop relay, relay with backhaul of
carrier aggregation, were not standardized in Release 10 LTE.
In the past few decades, a technological revolution has occurred that has changed
the way we live in dramatic ways. This technological revolution is the result of
the emergence and evolution of a wide variety of new wireless networking tech-
nologies. Now people using these technologies are able to access the network and
control many applications at will with their handheld devices anywhere, anytime.
Although these technologies have made a long lasting impact in the revolution, it
has also opened up various challenging issues which are yet to be resolved to make
them more efficient and cost-effective.
Rapid growth of wireless communication services in recent decades has created
a huge demand of radio spectrum. Spectrum scarcity and utilization inefficiency
limit the development of wireless networks. Cognitive radio is a promising tech-
nology that allows secondary users to reuse the underutilized licensed spectrum of
primary users. The major challenge for spectrum sharing is to achieve high spectrum
efficiency while making non-intrusive access to the licensed bands. This requires in-
formation of availability and quality of channel resources at secondary transmitters,
however, is difficult to be obtained perfectly in practice.
This book is an outgrowth of the pioneering development work done by InterDigital Com-
munication Corporation in 3rd Generation TDD WCDMA Technology. Many engineers
and managers were involved in this development, which spanned a wide range of tech-
nology areas, including system architecture, radio interface, radio modem design, radio
resource management and hardware/software implementation. In addition, TDD WCDMA
technology had many direct and indirect contributors across the globe in the context of
the development of the 3GPP TDD WCDMA Standard.
In the present era, low observability is one of the critical requirements in aerospace
sector, especially related to defense. The stealth technology essentially relates to
shaping and usage of radar absorbing materials (RAM) or radar absorbing struc-
tures (RAS). The performance of such radar cross section (RCS) reduction tech-
niques is limited by the bandwidth constraints, payload requirements, and other
structural issues. Moreover, with advancement of materials science, the structure
geometry no longer remains key decisive factor toward stealth.
District energy (DE) systems use central heating and/or cooling facilities to provide
heating and/or cooling services for communities. The advantages of district energy
over conventional heating and cooling include improved efficiency, reliability and
safety, reduced environmental impact, and for many situations better economics.
DE systems can be particularly beneficial when integrated with cogeneration plants
for electricity and heat, i.e., with combined heat and power (CHP) plants. One of
the main impediments to increased use of cogeneration-based district energy is a
lack of understanding of the behavior of integrated forms of such systems. This
book is aimed at providing information on district energy and cogeneration tech-
nologies, as well as systems that combine them.
