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Kalman Predictor Design for Frequency-adaptive
Scheduling of FDD OFDMA Uplinks.
Daniel Aronsson
and
Mikael Sternad
, Uppsala University.
IEEE Conference on Personal, Indoor and Mobile
Radio Communications (PIMRC),
Athens, Greece, September 2007.
© 2007 IEEE
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Abstract:
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Frequency-adaptive multiuser scheduling in
OFDM utilizes the
frequency-selective small-scale fading to
allocate subcarriers with
advantageous signal-to-noise ratio to each user.
Due to channel
time-variability and delays of the transmission control loop,
this will in general require channel prediction.
FDD (Frequency
Division Duplex) uplinks pose the most challenging prediction
problem: All sub-bands that may potentially
be allocated must here be
predicted for all involved user terminals, based on pilots
transmitted from all terminals.
This poses challenges with respect
to prediction accuracy, estimator complexity and
pilot overhead.
This paper explores the design,
performance and complexity
of Kalman predictors used for uplink prediction,
in the context of the EU WINNER project baseline
design system.
One conclusion is
that uplink prediction that is useful at
vehicular velocities in
4G systems operating at 3-5~GHz is indeed feasible.
However,
the channel predictability depends crucially on
the local fading environment, so predictors
should be based on models
of the Doppler spectrum for each terminal.
A set of Kalman predictors, each of which
simultaneously predicts the channels from
from a low number of users, using a low number
of pilot-bearing subcarriers as measurements,
provides good performance at reasonable computational
complexity.
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Related publications:
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Channel estimation and prediction
from a Bayesian perspective,
Licenciat Thesis by Daniel Aronsson, 2007.
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Eusipco 2007, focusing on comparing
the use of overlapping versus dedicated uplink pilots.
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IST Mobile Summit 2005 paper
that describes adaptive TDMA/OFDMA downlink and
uplink transmission.
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IEEE ICASSP 2005:
Channel estimation and prediction for adaptive
OFDMA/TDMA uplinks based on overlapping pilots.
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IEEE VTC-2003-Fall:
Channel estimation and prediction for adaptive OFDM
downlinks.
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Prediction of mobile radio channels,
Ph.D. Thesis by Torbjörn Ekman 2002.
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Proceedings of the IEEE
paper (2007) giving overview of adaptive
transmission in OFDMA systems.
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Source:
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Pdf, (164K)
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WINNER project
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The Wireless IP Project
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Main
entry in list of publications
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