Optimal blind nonlinear least-squares carrier phase and frequency offset estimation for general QAM modulations

Yan Wang, Erchin Serpedin, Philippe Ciblat

Research output: Contribution to journalArticle

59 Citations (Scopus)


This paper introduces a family of blind feedforward nonlinear least-squares (NLS) estimators for joint estimation of the carrier phase and frequency offset of general quadrature amplitude modulated (QAM) transmissions. As an extension of the Viterbi and Viterbi (V&V) estimator, a constellation-dependent optimal matched nonlinear estimator is derived such that its asymptotic (large sample) variance is minimized. A class of conventional monomial estimators is also proposed. The asymptotic performance of these estimators is established in closed-form expression and compared with the Cramér-Rao lower bound. A practical implementation of the optimal matched estimator, which is a computationally efficient approximation of the latter and exhibits negligible performance loss, is also derived. Finally, computer simulations are presented to corroborate the theoretical performance analysis and indicate that the proposed optimal matched nonlinear estimator improves significantly the performance of the classic fourth-power estimator.

Original languageEnglish
Pages (from-to)1040-1054
Number of pages15
JournalIEEE Transactions on Wireless Communications
Issue number5
Publication statusPublished - Sep 2003
Externally publishedYes



  • Blind estimation
  • Carrier phase
  • Frequency offset
  • Quadrature amplitude modulated (QAM) constellations
  • Synchronization

ASJC Scopus subject areas

  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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