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Summary: 388 IEEE COMMUNICATIONS LETTERS, VOL. 7, NO. 7, JULY 2003
Exploiting Error-Control Coding and Cyclic-Prefix in
Channel Estimation for Coded OFDM Systems
Ghazi A. Al-Rawi, Tareq Y. Al-Naffouri, Ahmad Bahai, and John Cioffi
Abstract--OFDM systems typically use coding and interleaving
across subchannels to exploit frequency diversity on frequency-
selective channels. This letter presents a low-complexity iterative
algorithm for blind and semi-blind joint channel estimation and
soft decoding in coded OFDM systems. The proposed algorithm
takes advantage of the channel finite delay-spread constraint and
the extra observation offered by the cyclic-prefix. It converges
within a single OFDM symbol and, therefore, has a minimum
latency.
Index Terms--Adaptive equalization, blind channel estimation,
iterative detection, multicarrier transmission.
I. INTRODUCTION
OFDM is an effective multicarrier modulation technique
for mitigating intersymbol interference (ISI) on fre-
quency-selective wireless channels. Estimating the channel
at the receiver enables coherent detection, which saves 3 dB
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