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Summary: Exploiting Error-Control Coding and Cyclic-Prefix in Channel
Estimation for Coded OFDM Systems
Ghazi Al-Rawit, Tareq Al-Naffourit, Ahmad Bahai*,and John Cioffit
+STARLab.
Stanford University
Stanford, CA 94305
Abstmct- OFDM systems typically use coding and in-
terleaving across subchannels to exploit Requency diver-
sity on frequency-selectivechannels. This paper presents e
low-complexity iterative algorithm for combined blind and
semi-blind channel estimation and so& decoding in coded
OFDM systems. Channel estimation is performed in the
time domain using the expectation maximization (EM) al-
gorithm to take advantage of the channel-length constraint
and the extra observation offered by the cyclic-prefix. The
proposed technique converges within e single OFDM ~ y m -
hol and, therefore, has a minimum latency and is suitable
for fast time-varying channels.
I. INTRODUCTION
OFDM is an effective multicarrier modulation technique
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