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

fYear

2008

fDate

19-21 March 2008

Firstpage

111

Lastpage

116

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/CISS.2008.4558505

Filename

4558505