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| [ Also see: Wireless
Resources IEEE
802.11 WLAN IEEE
802.16 WMAN IrDA
Spectrum
UWB
ZigBee
]
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Useful sites, articles and information for OFDM technologies.
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| CSU |
High-Throughput,
High-Performance OFDM via Pseudo-Orthogonal Carrier Interferometry
Coding (PDF) OFDM is susceptible to poor probability of error
performance in fading channels. To enhance OFDM’s performance,
many architectures utilize channel coding. The addition of coding,
adds both redundancy and frequency diversity, but comes at a cost of
reduced overall throughput (typically by a factor of 2). This paper
introduces a novel carrier interferometry phase coding to enhance
performance in OFDM systems without bandwidth expansion or decreased
throughput. It is shown that at a bit error rate of 10 -3 , this
method gains 14 dB over OFDM, equaling the performance of COFDM. A
system is now available demonstrating the benefits of Coded OFDM,
which maintains the throughput of OFDM. The cost is one of increased
receiver complexity. |
| IEEE |
IEEE
802.16 Tutorial Frequency Domain Equalization for 2-11 GHz
Broadband Wireless Systems. In this tutorial we survey recent
advances in frequency domain equalization (FDE) for single carrier
(SC) systems. SC modulation systems have lower peak-to
average-ratios than OFDM, and when combined with FDE, their
performance is at least as good as OFDM systems (in some cases
better); furthermore, they have the same reduced signal processing
complexity enjoyed by OFDM systems.
IEEE
802.16 Tutorials 802.16 MAN documents.
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| IEEE 802.16 Working Group on
Broadband Wireless Access Standards (wirelessman.org) |
Frequency
Domain Equalization for 2-11 GHz Broadband Wireless Systems (1/2001,
304Kb, PDF) Broadband wireless systems deployed in outdoor
non-line of sight environments may encounter delay spreads of over 5
to 10 us - which can cause potential intersymbol interference over
50 or more data symbol intervals. OFDM (orthogonal frequency
division multiplexing) has been suggested to combat this ISI problem
with reasonable complexity. However OFDM systems generate high
transmitted peak-to-average ratios and are sensitive to phase noise;
this can increase RF subsystem cost and complexity. |
| mobilecomms-technology |
T-Mobile
FLASH-OFDM Mobile Broadband Network, Slovakia In October 2005
T-Mobile launched a new and faster mobile broadband internet access
network in Slovakia. The network is Europe's first commercial mobile
broadband service (also a world first) and uses Flarion
Technologies' (now acquired by Qualcomm Inc. for $600 million) Fast,
Low-latency Access with Seamless Handoff - Orthogonal Frequency
Division Multiplexing (FLASH-OFDM) network technology. |
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