During the past decade, many wireless communication techniques have been
developedto achievevariousgoals suchas higherdata rate,morerobustlink quality,
and higher number of users in a given bandwidth. For wireless communication
systems, depending on the availability of a feedback link, two approaches can be
considered: namely open and closed loop. Open loop communication system that
does not exploit the channel knowledge at the transmitter is now well understood
from both a theoretical and practical point of view.
The writing of this book was prompted by two main developments in wireless
communications in the past decade. First is the huge surge of research activities in
physical-layer wireless communication theory. While this has been a subject of study
since the 60’s, recent developments in the field, such as opportunistic and multi-input
multi-output (MIMO) communication techniques, have brought completely new per-
spectives on how to communicate over wireless channels.
When digital media is perceived only as a tool to deliver content the potential for
using its affordances to explore meaning is lost. Rather than seeing media only as
an access point, we can view it as a way to enhance the expressiveness of content.
Today blogs, wikis, messaging, mash-ups, and social media (Facebook, Twitter,
YouTube and others) offer authors ways to create narrative meaning that refl ects
our new media culture. We can look to the past for similarities and parallels to
better understand how to use social media as a creative tool with which to
dialogue, collaborate, and create interactive narratives.
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.
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.
When we started thinking about writing the first edition of this book a few years ago, we had been
working together for more than five years on the borderline between propagation and signal processing.
Therefore, it is not surprising that this book deals with propagation models and design tools for MIMO
wireless communications. Yet, this book should constitute more than a simple combination of these
two domains. It hopefully conveys our integrated understanding of MIMO, which results from endless
controversial discussions on various multi-antenna related issues, as well as various interactions with
numerous colleagues. Obviously, this area of technology is so large that it is beyond our aim to cover all
aspects in details. Rather, our goal is to provide researchers, R&D engineers and graduate students with
a comprehensive coverage of radio propagation models and space–time signal processing techniques
for multi-antenna, multi-user and multi-cell networks.
When we started thinking about writing this book, we had been working together for more
than five years on the borderline between propagation and signal processing.Therefore, it
is not surprising that this book deals with propagation models and design tools for MIMO
wirelesscommunications.Yet, thisbookshouldconstitutemorethanasimplecombination
of these two domains. It hopefully conveys our integrated understanding of MIMO, which
results from endless controversial discussions on various multi-antenna related issues, as
well as various interactions with numerous colleagues. Obviously, this area of technology
is so large that it was beyond our aim to cover all aspects in details. Rather, our goal has
been to provide researchers, R&D engineers and graduate students with a comprehensive
coverage of radio propagation models and space–time coding techniques.
One of the very first books published on the social impact of the mobile phone
was Timo Kopomaa’s The City in Your Pocket: Birth of the Mobile Information Society.
The book, published in 2000, was based on research that Kopomaa had under-
taken for Nokia and Sonera as part of his doctoral studies in the Centre for Urban
and Regional Studies at the Helsinki University of Technology. The first line he
writes in the book is peculiar: ‘Mobile communication is not a serious matter’. By
this, we assume he is referring to a view of the world that would regard the mobile
phone as little more than an unremarkable fact of everyday life – a simple play-
thing for the young, or a productivity tool for the business executive and busy
parent.
The family of recent wireless standards included the optional employment of Multiple-Input
Multiple-Output(MIMO)techniques.This was motivatedby the observationaccordingto the
classic Shannon–Hartley law that the achievable channel capacity increases logarithmically
with the transmit power. In contrast, the MIMO capacity increases linearly with the number
of transmit antennas, provided that the number of receive antennas is equal to the number
of transmit antennas. With the further proviso that the total transmit power is increased in
proportion to the number of transmit antennas, a linear capacity increase is achieved upon
increasing the transmit power, which justifies the spectacular success of MIMO systems.
