Title :
NDA SNR estimation: CRLBs and EM based estimators
Author_Institution :
ViaSat Inc., Carlsbad, CA
Abstract :
Signal to noise ratio (SNR) estimation is an important problem in many communication systems. SNR often needs to be estimated in the presence of unknown transmitted data symbols in a non data aided (NDA) manner. In this paper we derive a methodology to calculate the Cramer-Rao lower bound (CRLB) of NDA SNR estimation in an additive white Gaussian noise (AWGN) channel for any symmetric constellation. In particular, the CRLB is evaluated and presented for QPSK, 8PSK, 16QAM, 32QAM, 16APSK and 32APSK constellations. We also present an Expectation-Maximization (EM) algorithm based iterative estimator, valid for any arbitrary constellation, which performs very close to the CRLBs at all SNRs of practical interest and discuss issues regarding this iterative algorithm such as initialization and convergence speed.
Keywords :
AWGN channels; amplitude shift keying; convergence; expectation-maximisation algorithm; quadrature amplitude modulation; quadrature phase shift keying; APSK; Cramer-Rao lower bound; additive white Gaussian noise channel; arbitrary constellation; convergence speed; expectation-maximization algorithm; iterative algorithm; non data aided manner; quadrature amplitude modulation; quadrature phase shift keying; signal to noise ratio estimation; AWGN; Additive white noise; Binary phase shift keying; Demodulation; Digital video broadcasting; Iterative algorithms; Phase estimation; Quadrature amplitude modulation; Quadrature phase shift keying; Signal to noise ratio; 16APSK; 32APSK; CRLB; DVB-S2; EM Algorithm; NDA SNR Estimation; QPSK; SNR Estimation;
Conference_Titel :
TENCON 2008 - 2008 IEEE Region 10 Conference
Conference_Location :
Hyderabad
Print_ISBN :
978-1-4244-2408-5
Electronic_ISBN :
978-1-4244-2409-2
DOI :
10.1109/TENCON.2008.4766719
