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FEATURE
ARTICLES
Spectrum Considerations for Public Safety in the
United States
Due to the narrowband technologies used
in public safety communications systems, public safety agencies have
been limited primarily to voice services and low-speed data transfer
on their private networks. In contrast, the commercial cellular
sector now offers a large portfolio of services. The authors
describe some of the factors driving the expansion of spectrum
allocated to public safety agencies.
Tewfik L. Doumi, Bell
Labs, Lucent Technologies
Evolving Public Safety Communication Systems by
Integrating WLAN and TETRA Networks
The author
contributes to the evolution of public safety communication systems
by specifying a novel solution for integrating WLAN and Terrestrial
Trunked Radio (TETRA) networks. The specified solution allows TETRA
terminals to interface to the TETRA Switching and Management
Infrastructure (SwMI) over a broadband WLAN radio access network,
instead of the conventional narrowband TETRA radio
network.
Apostolis K. Salkintzis, Motorola
The Resurgence of Push-to-Talk Technologies
Push-to-talk (PTT) technologies date back to the advent
of the telegraph and more recently have been the domain of
traditional land mobile radio (LMR) networks. The past few years
have brought about a resurgence in PTT as a service offered by
commercial providers. The authors discuss some of the emerging
technologies that relate to today's PTT service. They also discuss
the market and financial implications of commercial PTT on current
LMR deployments.
Luiz A. DaSilva, George E. Morgan, Charles W.
Bostian, Dennis G. Sweeney, Scott F. Midkiff, Jeffrey H. Reed, and
Christie Thompson, Virginia Polytechnic Institute and State
University; William G. Newhall, Ball Aerospace & Technologies
Corp. ; Brian Woerner, West Virginia University
Mobile Responder Communication Networks for Public
Safety
The authors propose a paradigm shift from the
prevailing public safety model of disparate, agency-owned and
-operated Land Mobile Radio networks to Mobile Responder
Communication Networks (MRCNs) that are created by unifying
communications resources and are shared across cooperating public
safety agencies.
Krishna Balachandran, Kenneth C. Budka, Thomas
P. Chu, Tewfik L. Doumi, and Joseph H. Kang, Bell Labs, Lucent
Technologies
The Acoustic Properties of SCBA Equipment and Its
Effects on Speech Communication
The Self-Contained
Breathing Apparatus (SCBA) mask air delivery system is essential
equipment in certain public service activities. It is important that
high-quality and reliable communications are maintained when SCBA
equipment is employed. The authors characterize some of the effects
of SCBA equipment on speech quality and intelligibility, and they
outline parameters that should be considered in communications
system design and interfacing.
William M. Kushner, S. Michelle
Harton, Robert J. Novorita,
and Michael J. McLaughlin, Motorola
Vehicle-to-Vehicle Wireless Communication Protocols
for Enhancing Highway Traffic Safety
The authors present
an overview of highway cooperative collision avoidance (CCA), which
is an emerging vehicular safety application using the IEEE- and
ASTM-adopted Dedicated Short Range Communication (DSRC)
standard.
Subir Biswas, Michigan State University; Raymond
Tatchikou, University of Kaiserslautern; Francois Dion, Michigan
State University
Cross-Layer Feedback Architecture for Mobile Device
Protocol Stacks
Applications using traditional protocol
stacks (e.g., TCP/IP) from wired networks do not function efficiently
in mobile wireless environments. This is primarily due to the layered
architecture and implementation of protocol stacks. One mechanism to
improve the efficiency of the stack is cross-layer feedback, that
is, making information from within one layer available to another
layer of the stack.
Vijay T. Raisinghani and Sridhar Iyer,
Indian Institute of Technology Bombay
CrossTalk: Cross-Layer Decision Support Based on
Global Knowledge
The dynamic nature of ad hoc networks
makes system design a challenging task. Mobile ad hoc networks
suffer from severe performance problems due to the shared,
interference-prone, and unreliable medium, and routes can be
unstable. In such environments cross-layer architectures are a
promising new approach, as they can adapt protocol behavior to
changing networking conditions.
Rolf Winter and Jochen H.
Schiller, Freie Universität Berlin; Navid Nikaein and
Christian Bonnet, Institut Eurecom
Cross-Layer-Based Modeling for Quality of Service
Guarantees in Mobile Wireless Networks
The authors
propose a cross-layer approach to investigate the impact of the
physical-layer infrastructure on the data-link-layer QoS performance
in mobile wireless networks.
Xi Zhang and Jia Tang, Texas
A&M University; Hsiao-Hwa Chen, National Sun Yat Sen University
; Song Ci, University of Massachusetts, Boston ; Mohsen Guizani,
Western Michigan University
Toward an Improvement of H.264 Video Transmission over
IEEE 802.11e through a Cross-Layer Architecture
The
recently developed H.264 video standard achieves efficient encoding
over a bandwidth ranging from a few kilobits per second to several
megabits per second. Hence, transporting H.264 video is expected to
be an important component of many wireless multimedia services.
However, due to wireless channel characteristics and lack of QoS
support, the basic 802.11-based channel access procedure is merely
sufficient to deliver non-real-time traffic, and delivery should be
augmented by appropriate mechanisms.
Adlen Ksentini and
Mohamed Naimi, LICP Lab; Abdelhak Guéroui, PRiSM Lab
Optimized Video Streaming over 802.11 by Cross-Layer
Signaling
Seamless video streaming over wireless links
imposes strong demands on video codecs and the underlying network.
It is not sufficient that only the video codec or only the radio
adapts to changes in the wireless link quality; efforts should be
applied in both layers, and — if possible —
synchronized.
Ivaylo Haratcherev, Jacco Taal, Koen Langendoen,
Reginald Lagendijk, and Henk Sips, Delft University of Technology
Application-Driven Cross-Layer Optimization for Video
Streaming over Wireless Networks
Mobile multimedia
applications require networks that optimally allocate resources and
adapt to dynamically changing environments. Cross-layer design is a
new paradigm that addresses this challenge by optimizing
communication network architectures across traditional layer
boundaries.
S. Khan, Y. Peng, and E. Steinbach, Technische
Universität München ; M. Sgroi and W. Kellerer, Docomo
Communications Laboratories Europe GmbH
Cross-Layer Activity Management in an 802.15.4 Sensor
Network
Sensor networks operate under conflicting
requirements of maintaining the desired value of information
throughput while simultaneously maximizing the lifetime of individual
nodes. In doing so, the characteristics of the operating environment
must be taken into account as well. The authors consider activity
management of sensor nodes in a beacon-enabled IEEE
802.15.4-compliant network.
Jelena Mišic, Shairmina Shafi,
and Vojislav B. Mišic, University of Manitoba
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