Title :
Recursive least squares estimation of QAM and QPSK signals in the presence of frequency offset
Author :
Denno, Satoshi ; Saito, Yoichi
Author_Institution :
NTT Radio Commun. Syst. Labs., Kanagawa, Japan
Abstract :
Adaptive frequency and phase control methods for differential/quasi-coherent phase detection based on recursive least squares (RLS) estimation in the presence of frequency offset are discussed. An RLS estimator for differential detection is presented and its convergence rate is derived. An RLS estimator is proposed for quasi-coherent detection that can accurately demodulate in the presence of frequency offset while achieving fast convergence. It was verified experimentally that the estimators for quadrature amplitude modulation (QAM) quasi-coherent detection and π/4 quadrature phase shift keying (QPSK) differential detection had good performance in the presence of frequency offset, and that the RLS estimator attained convergence in 10 symbols
Keywords :
adaptive control; amplitude modulation; cellular radio; convergence of numerical methods; demodulation; frequency control; least squares approximations; parameter estimation; phase control; phase shift keying; signal detection; QAM; QPSK; adaptive frequency control; adaptive phase control; cellular radio; convergence rate; differential detection; frequency offset; performance; pi /4 quadrature phase shift keying; quadrature amplitude modulation; quasi-coherent phase detection; recursive least squares estimation; Amplitude estimation; Convergence; Frequency estimation; Least squares approximation; Phase detection; Phase estimation; Phase frequency detector; Quadrature amplitude modulation; Quadrature phase shift keying; Resonance light scattering;
Conference_Titel :
Communications, 1992. ICC '92, Conference record, SUPERCOMM/ICC '92, Discovering a New World of Communications., IEEE International Conference on
Conference_Location :
Chicago, IL
Print_ISBN :
0-7803-0599-X
DOI :
10.1109/ICC.1992.268082
