Title :
CFO estimation in OFDM systems and effects of nonlinear power amplifiers
Author :
Malipatil, Amaresh V. ; Zhou, Hao ; Huang, Yih-Fang
Author_Institution :
Dept. of Electr. Eng., Univ. of Notre Dame, Notre Dame, IN
Abstract :
It is well known that Carrier frequency offset (CFO) is a performance limiting factor in orthogonal frequency division multiplexing (OFDM) systems. In this paper, we present maximum-likelihood estimators (MLE) for the CFO in OFDM systems in static and time-varying channels and evaluate the Cramer-Rao lower bounds (CRLB) for both cases. In addition, we examine the effect of power amplifiers´ (PA) nonlinearity, which can be either memoryless or with memory. This nonlinearity impacts the system performance in several ways including higher BER and degraded channel estimation accuracy. In this paper, we analyze the effect of PA nonlinearity with memory on CFO estimation, quantifying the performance degradation caused by PA nonlinearity and the gain provided by employing predistortion filters.
Keywords :
OFDM modulation; channel estimation; error statistics; power amplifiers; time-varying channels; BER; CFO estimation; Cramer-Rao lower bounds; OFDM systems; carrier frequency offset; channel estimation; maximum-likelihood estimators; nonlinear power amplifiers; orthogonal frequency division multiplexing systems; predistortion filters; static channels; time-varying channels; Bit error rate; Cause effect analysis; Channel estimation; Degradation; Maximum likelihood estimation; OFDM; Performance analysis; Power amplifiers; System performance; Time-varying channels;
Conference_Titel :
Information Sciences and Systems, 2008. CISS 2008. 42nd Annual Conference on
Conference_Location :
Princeton, NJ
Print_ISBN :
978-1-4244-2246-3
Electronic_ISBN :
978-1-4244-2247-0
DOI :
10.1109/CISS.2008.4558505
