TY - GEN
T1 - Limitations of Constrained CRB and an Alternative Bound
AU - Nitzan, Eyal
AU - Routtenberg, Tirza
AU - Tabrikian, Joseph
N1 - Publisher Copyright: © 2018 IEEE.
PY - 2018/8/29
Y1 - 2018/8/29
N2 - The constrained Cramér-Rao bound (CCRB) is a mean-squared-error (MSE) lower bound for non-Bayesian constrained parameter estimation under some unbiasedness conditions. In this paper, we demonstrate limitations of this bound in the case of nonlinear parametric constraints. We consider the problem of constant modulus signal estimation. It is shown that in this problem the CCRB unbiasedness conditions are too restrictive and that the commonly-used constrained maximum likelihood (CML) estimator does not satisfy them and has lower MSE than the CCRB. An alternative lower bound, which is based on the Lehmann-unbiasedness conditions, is used as an alternative benchmark for constrained parameter estimation. As opposed to the CCRB, it is shown that this alternative bound is valid for the CML estimator in the considered problem.
AB - The constrained Cramér-Rao bound (CCRB) is a mean-squared-error (MSE) lower bound for non-Bayesian constrained parameter estimation under some unbiasedness conditions. In this paper, we demonstrate limitations of this bound in the case of nonlinear parametric constraints. We consider the problem of constant modulus signal estimation. It is shown that in this problem the CCRB unbiasedness conditions are too restrictive and that the commonly-used constrained maximum likelihood (CML) estimator does not satisfy them and has lower MSE than the CCRB. An alternative lower bound, which is based on the Lehmann-unbiasedness conditions, is used as an alternative benchmark for constrained parameter estimation. As opposed to the CCRB, it is shown that this alternative bound is valid for the CML estimator in the considered problem.
KW - Constrained Cramér-Rao bound (CCRB)
KW - Lehmann-unbiasedness
KW - constant modulus signal estimation
KW - constrained parameter estimation
KW - mean-squared-error (MSE)
UR - http://www.scopus.com/inward/record.url?scp=85053826011&partnerID=8YFLogxK
U2 - https://doi.org/10.1109/SSP.2018.8450829
DO - https://doi.org/10.1109/SSP.2018.8450829
M3 - Conference contribution
SN - 9781538615706
T3 - 2018 IEEE Statistical Signal Processing Workshop, SSP 2018
SP - 841
EP - 845
BT - 2018 IEEE Statistical Signal Processing Workshop, SSP 2018
T2 - 20th IEEE Statistical Signal Processing Workshop, SSP 2018
Y2 - 10 June 2018 through 13 June 2018
ER -