Frequency domain characterization of los nonfading indoor wireless LAN channel employing frequency and polarization Diversity in the 63.4 to 65.4GHz band
ieee754的標準，原英文版的！Twenty years ago anarchy threatened floating-point arithmetic. Over a dozen commercially significant arithmetics
boasted diverse wordsizes, precisions, rounding procedures and over/underflow behaviors, and more were in the
works. “Portable” software intended to reconcile that numerical Diversity had become unbearably costly to
develop.
Thirteen years ago, when IEEE 754 became official, major microprocessor manufacturers had already adopted it
despite the challenge it posed to implementors. With unprecedented altruism, hardware designers had risen to its
challenge in the belief that they would ease and encourage a vast burgeoning of numerical software. They did
succeed to a considerable extent. Anyway, rounding anomalies that preoccupied all of us in the 1970s afflict only
CRAY X-MPs — J90s now.
Abstract—In the future communication applications, users
may obtain their messages that have different importance levels
distributively from several available sources, such as distributed
storage or even devices belonging to other users. This
scenario is the best modeled by the multilevel Diversity coding
systems (MDCS). To achieve perfect (information-theoretic)
secrecy against wiretap channels, this paper investigates the
fundamental limits on the secure rate region of the asymmetric
MDCS (AMDCS), which include the symmetric case as a special
case. Threshold perfect secrecy is added to the AMDCS model.
The eavesdropper may have access to any one but not more than
one subset of the channels but know nothing about the sources,
as long as the size of the subset is not above the security level.
The question of whether superposition (source separation) coding
is optimal for such an AMDCS with threshold perfect secrecy
is answered. A class of secure AMDCS (S-AMDCS) with an
arbitrary number of encoders is solved, and it is shown that linear
codes are optimal for this class of instances. However, in contrast
with the secure symmetric MDCS, superposition is shown to
be not optimal for S-AMDCS in general. In addition, necessary
conditions on the existence of a secrecy key are determined as a
design guideline.
Smart City Networks: Through the Internet of Things is composed of research
results, analyses, and ideas, which focus on a Diversity of interconnected factors
relating with urbanization, its “smartness,” and overarching “internet of things
(IoT).” The latter refers to interconnected objects and devices – through compu-
tational operations – which can receive signals and actuate systems.
Relaying techniques, in which a source node communicates to a destination node
with the help of a relay, have been proposed as a cost-effective solution to address
the increasing demand for high data rates and reliable services over the air. As
such, it is crucial to design relay systems that are able to not only provide high
spectral efficiency, but also fully exploit the Diversity of the relay channel.
Employing multiple transmit and receive antennas, namely using multi-input multi-output
(MIMO) systems, has proven to be a major breakthrough in providing reliable wireless
communication links. Since their invention in the mid-1990s, transmit Diversity, achieved
through space-time coding, and spatial multiplexing schemes have been the focus of much
research in the area of wireless communications.
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.
In this book, we study the interference cancellation and detection problem in
multiantenna multi-user scenario using precoders. The goal is to utilize multiple
antennas to cancel the interference without sacrificing the Diversity or the com-
plexity of the system.
Multi-carrier modulation? Orthogonal Frequency Division Multi-
plexing (OFDM) particularly? has been successfully applied to
a wide variety of digital communications applications over the past
several years. Although OFDM has been chosen as the physical layer
standard for a Diversity of important systems? the theory? algorithms?
and implementation techniques remain subjects of current interest.
This is clear from the high volume of papers appearing in technical
journals and conferences.
