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FEATURE
ARTICLES
Streaming Processors for Next-Generation Mobile
Imaging Applications
Next-generation mobile devices
will continue to demand high processing power for imaging
applications. The expected performance is in the class of
supercomputers, but delivered with limited energy and memory
bandwidth for embedded systems. This article advocates a streaming
computation model that leverages the deterministic access patterns
in imaging applications to deliver the necessary processing
throughput.
Sek M. Chai, Silviu Chiricescu, Ray Essick, Brian
Lucas, Phil May, Kent Moat, James M. Norris, and Mike Schuette,
Motorola Labs; Abelardo López-Lagunas, Instituto
Tecnológico y de Estudios Superiores de Monterrey Campus
Toluca
Low-Power 3D Graphics Processors for Mobile Terminals
A full 3D graphics pipeline is investigated, and
optimizations of graphics architecture are assessed for satisfying
the performance requirements and overcoming the limited system
resources found in mobile terminals. Two mobile 3D graphics processor
architectures, RAMP and DigiAcc, are proposed based on the analysis,
and a prototype development platform (REMY) is
implemented.
Ju-Ho Sohn, Yong-Ha Park, Chi-Weon Yoon, Ramchan
Woo, Se-Jeong Park,
and Hoi-Jun Yoo, KAIST
A CMOS 868/915 MHz Direct Conversion ZigBee
Single-Chip Radio
In this article the 868/915 MHz radio
transceiver specifications have been derived for IEEE 802.15.4, a
low-rate, low-cost, and low-power network standard. The radio
specifications include parameters such as noise figure,
nonlinearity, channel filtering, phase noise of local oscillator,
dynamic range, and bit resolutions of analog-to-digital and
digital-to-analog converters.
Nam-Jin Oh and Sang-Gug Lee,
Information and Communications University; Jinho Ko, Phychips
Inc.
Cross-Layer Design: A Survey and the Road Ahead
Of late, there has been an avalanche of cross-layer
design proposals for wireless networks. A number of researchers
have looked at specific aspects of network performance and,
approaching cross-layer design via their interpretation of what it
implies, have presented several cross-layer design proposals. These
proposals involve different layers of the protocol stack, and
address both cellular and ad hoc networks.
Vineet Srivastava,
Institute for Infocomm Research and National University of Singapore
; Mehul Motani, National University of Singapore
Cross-Layer Design for Resource Allocation in 3G
Wireless Networks and Beyond
Cross-layer design
approaches are critical for efficient utilization of the scarce
radio resources with QoS provisioning in the third-generation
wireless networks and beyond. Better system performance can be
obtained from information exchanges across protocol layers, which
may not be available in the traditional layering
architecture.
Hai Jiang, Weihua Zhuang,
and Xuemin (Sherman) Shen, University of Waterloo
Utility-Based Resource Allocation and Scheduling in
OFDM-Based Wireless Broadband Networks
The authors
discusse downlink resource allocation and scheduling for OFDM-based
broadband wireless networks. They present a cross-layer resource
management framework leveraged by utility optimization. It includes
utility-based resource management and QoS architecture, resource
allocation algorithms, rate-based and delay-based multichannel
scheduling that exploits wireless channel and queue information,
and theoretical exploration of the fundamental mechanisms in wireless
resource management, such as capacity, fairness, and
stability.
Guocong Song, Motorola Inc.; Ye (Geoffrey) Li,
Georgia Institute of Technology
Design and Implementation of a Simulator Based on a
Cross-Layer Protocol between MAC and PHY Layers in a WiBro
Compatible IEEE 802.16e OFDMA System
The authors propose
cross-layer design frameworks for 802.16e OFDMA systems that are
compatible with WiBro based on various kinds of cross-layer
protocols for performance improvement.
Taesoo Kwon, Howon Lee,
Sik Choi, Juyeop Kim, and Dong-Ho Cho, Korea Advanced Institute of
Science and Technology; Sunghyun Cho, Sangboh Yun, Won-Hyoung Park,
and Kiho Kim, Samsung Advanced Institute of Technology
Trade-off Analysis of PHY-Aware MAC in Low-Rate
Low-Power UWB Networks
The choices made for
rate-efficient designs are not necessarily optimal when considering
energy efficiency. Hence, there is a need to understand the design
trade-offs in very-low-power networks, which is the aim of this
article.
Alaeddine El Fawal, Jean-Yves Le Boudec, Ruben Merz,
and Bozidar Radunovic, EPFL, School for Computer and Communication
Sciences; Jörg Widmer, DoCoMo Euro-Labs; Gian Mario Maggio,
STMicroelectronics
Topology-Aided Cross-Layer Fast Handoff Designs for
IEEE 802.11/Mobile IP Environments
This study first
reviews state-of-the-art fast handoff techniques for IEEE 802.11 or
Mobile IP networks. Based on that review, topology-aided cross-layer
fast handoff designs are proposed for Mobile IP over IEEE 802.11
networks. Time-sensitive applications, such as voice over IP
(VoIP), cannot tolerate the long layer 2 plus layer 3 handoff
delays that arise in IEEE 802.11/Mobile IP environments. Cross-layer
designs are increasingly adopted to shorten the handoff latency
time. Handoff-related layer 2 triggers may reduce the delay between
layer 2 handoff completion and the associated layer 3 handoff
activation.
Chien-Chao Tseng, National Chiao-Tung University ;
Li-Hsing Yen, Chung Hua University; Hung-Hsin Chang and Kai-Cheng
Hsu, National Chiao-Tung University
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