Cramer-Rao lower bounds for QAM phase and frequency estimation

Author

Rice, Feng ; Cowley, Bill ; Moran, Bill ; Rice, Mark

Author_Institution

Cooperativre Res, Center for Sensor Signal & Inf. Processing, South Australia Univ, Mawson Lakes, SA, Australia

Volume

49

Issue

9

fYear

2001

fDate

9/1/2001 12:00:00 AM

Firstpage

1582

Lastpage

1591

Abstract

In this paper, we present the true Cramer-Rao lower bounds (CRLBs) for the estimation of phase offset for common quadrature amplitude modulation (QAM), PSK, and PAM signals in AWGN channels. It is shown that the same analysis also applies to the QAM, FSK, and PAM CRLBs for frequency offset estimation. The ratio of the modulated to the unmodulated CRLBs is derived for all QAM, PSK, and PAM signals and calculated for specific cases of interest. This is useful to determine the limiting performance of synchronization circuits for coherent receivers without the need to simulate particular algorithms. The hounds are compared to the existing true CRLBs for an unmodulated carrier wave (CW), BPSK, and QPSK. We investigated new and existing QAM phase estimation algorithms in order to verify the new phase CRLB. This showed that new minimum distance estimator performs close to the QAM bound and provides a large improvement over the power law estimator at moderate to high signal-to-noise ratios

Keywords

AWGN channels; frequency estimation; frequency shift keying; phase estimation; pulse amplitude modulation; quadrature amplitude modulation; quadrature phase shift keying; receivers; synchronisation; AWGN channels; BPSK; CRLB; Cramer-Rao lower bounds; FSK; PAM signals; PSK; QAM; QPSK; coherent receivers; frequency estimation; frequency offset; minimum distance estimator; modulated CRLB; performance; phase estimation; phase offset; quadrature amplitude modulation; signal-to-noise ratio; synchronization circuits; unmodulated CRLB; unmodulated carrier wave; AWGN channels; Amplitude estimation; Binary phase shift keying; Circuit simulation; Frequency estimation; Frequency shift keying; Frequency synchronization; Phase estimation; Phase shift keying; Quadrature amplitude modulation;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/26.950345

Filename

950345