EW2008 - Tutorials
T1 Modeling Wireless Channels: From Basic to High-Fidelity and
Non-Stationary Statistical Channel Models
prof. David W. Matolak
Ohio University, School of Electrical Engineering & Computer
Science, Athens, Ohio, USA
http://www.ent.ohiou.edu/~dmatolak/index.htm
Abstract
This tutorial will provide participants with knowledge of wireless
channel characteristics and how to model them, for physical- and
higher-layer investigations. We cover classical models, but also focus
on newer models that represent channel effects with greater realism
than classical models. After a brief review of fundamentals,
statistical fading models are summarized, including descriptions of
new/atypical distributions. Propagation environment classification then
leads to descriptions of frequency flat and frequency selective fading.
Classical WSSUS channels are reviewed, and the WSSUS assumptions are
then relaxed to investigate correlated scattering and statistical
non-stationarity. We show how statistical nonstationarity enables
long-term (wide area) channel models, useful for cross-layer designs.
Spatial (antenna diversity) extensions, MIMO, and optical channels are
briefly reviewed. Some of the author’s measurement results are also
employed for illustration.
The physical layer (PHY) forms the foundation for any communication
system. For wireless systems, the channel often presents a particularly
challenging PHY subsystem, whose characteristics need to be known for
efficient communication. Classical, statistically stationary models for
the wireless channel are simply inadequate for depicting channel
effects realistically—they oversimplify the actual propagation channel
in important ways, particularly for future systems that will operate
over long terms, wide areas, and without centralized control. New
applications such as ultrawideband (UWB) and vehicle-to-vehicle (VTV)
communications also require re-investigation of traditional channel
characterizations. New models for wireless channels that better
represent actual conditions will be vital for maximizing system
ubiquity and capacity. Disseminating knowledge of these models will aid
in research, development, and deployment of new wireless systems in
multiple application areas.
Scope and Intended Audience
This tutorial is an in-depth study of one particular topic, not a
survey of several topics. Participants in this tutorial should have an
electrical engineering background, preferably a bachelor’s degree or
higher in electrical or computer engineering, or computer science.
Persons with physics or mathematics degrees may also benefit from the
course. A good knowledge of probability and statistics, linear systems,
and modulation, is recommended. Anyone who must evaluate, specify,
compare, or deploy wireless systems over channels in multiple
environments would benefit from this course. Graduate students and
researchers who are interested in more information, but not expert in
this topic, should also benefit.
T2 From Software Radio to Cognitive Radio: the technical challenges
prof. Jacques Palicot
SUPELEC, Cesson-Sevigne, France
Abstract
ISSPIT 07, December 15-18, Cairo, Egypt
In this presentation
we will define Cognitive Radio starting from the needs which have
motivated this new concept. We will demonstrate that it has developed
from natural telecommunication evolution to global convergence of
networks and services. Today, for a large number of players in the
telecommunication field, this concept consists primarily of
intelligently and efficiently managing the spectrum, but we will
expand this approach by showing that it can affect all segments of a
telecommunications system. This concept follows the classical circle
of intelligent (i-e sensing the information, analysis, training,
decision, and action). Some very important technological problems
exist in this circle. We will, in particular talk of sensors, which
need advance signal processing. The aspect of intelligence management
in terms of a software architecture dealing at the same time
information from the sensors and decisions (linked with the
management of the reconfiguration of equipment), will also be
treated. In our vision, Cognitive Radio is supported by Software
Radio Technology. This corresponds to the second main set of problems
that we will present. Indeed, all classical problems of Software
Radio exist in Cognitive Radio (Front End radio, Non-linearity,
hardware, reconfiguration management, etc. We shall not deal in
detail all of these issues, but only those that we believe are
particularly important shall be discussed."
The
presentation will make reference and build on the work carried out by
Signal Communications and Electronics Embedded (SCEE) SUPELEC team in
Rennes Campus.
Jan Sykora, last update 7.4.2008