TY - JOUR
T1 - UWB sparse/diffuse channels, part II
T2 - Estimator analysis and practical channels
AU - Michelusi, Nicolò
AU - Mitra, Urbashi
AU - Molisch, Andreas F.
AU - Zorzi, Michele
N1 - Funding Information:
Manuscript received September 12, 2011; revised March 12, 2012; accepted June 07, 2012. Date of publication June 22, 2012; date of current version September 11, 2012. The associate editor coordinating the review of this manuscript and approving it for publication was Dr. Xavier Mestre. This work was supported in part by the following grants and organizations: ONR N00014-09-1-0700, NSF CNS-0832186, NSF CNS-0821750 (MRI), Aldo Gini Foundation (Padova, Italy).
PY - 2012
Y1 - 2012
N2 - In this two-part paper, the problem of channel estimation in Ultra Wide-Band (UWB) systems is investigated. In Part I, a novel Hybrid Sparse/Diffuse (HSD) model is proposed for the UWB channel, and new channel estimation strategies are designed for this model. In this paper (Part II), a Mean-Squared Error (MSE) analysis of the Generalized MMSE and Generalized Thresholding Estimators developed in Part I is performed, for the asymptotic regimes of low and high SNR. The analysis quantifies the achievable MSE performance of these schemes over unstructured estimators. Specifically, we prove that it is beneficial to be conservative in the estimation of the sparse component, i.e., to assume that the sparse component is sparser than it actually is. Moreover, we analyze the scenario with a non-orthogonal pilot sequence, and establish a connection between the Generalized Thresholding estimator and conventional sparse approximation algorithms proposed in the literature. In addition to the theoretical analysis, these channel estimation schemes are evaluated in a more realistic geometry-based channel emulator, for which the HSD model developed in Part I is an approximation. The numerical results are shown to match the expected asymptotic MSE behavior. Moreover, the proposed estimation techniques are shown to outperform conventional unstructured and purely sparse estimators, from both an MSE and a bit error rate perspectives, even for the realistic geometry-based channel model.
AB - In this two-part paper, the problem of channel estimation in Ultra Wide-Band (UWB) systems is investigated. In Part I, a novel Hybrid Sparse/Diffuse (HSD) model is proposed for the UWB channel, and new channel estimation strategies are designed for this model. In this paper (Part II), a Mean-Squared Error (MSE) analysis of the Generalized MMSE and Generalized Thresholding Estimators developed in Part I is performed, for the asymptotic regimes of low and high SNR. The analysis quantifies the achievable MSE performance of these schemes over unstructured estimators. Specifically, we prove that it is beneficial to be conservative in the estimation of the sparse component, i.e., to assume that the sparse component is sparser than it actually is. Moreover, we analyze the scenario with a non-orthogonal pilot sequence, and establish a connection between the Generalized Thresholding estimator and conventional sparse approximation algorithms proposed in the literature. In addition to the theoretical analysis, these channel estimation schemes are evaluated in a more realistic geometry-based channel emulator, for which the HSD model developed in Part I is an approximation. The numerical results are shown to match the expected asymptotic MSE behavior. Moreover, the proposed estimation techniques are shown to outperform conventional unstructured and purely sparse estimators, from both an MSE and a bit error rate perspectives, even for the realistic geometry-based channel model.
KW - Bayesian estimation
KW - Channel estimation
KW - Channel modeling
KW - Sparse approximations
KW - Ultra wideband
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U2 - 10.1109/TSP.2012.2205682
DO - 10.1109/TSP.2012.2205682
M3 - Article
AN - SCOPUS:84866518978
SN - 1053-587X
VL - 60
SP - 5320
EP - 5333
JO - IEEE Transactions on Signal Processing
JF - IEEE Transactions on Signal Processing
IS - 10
M1 - 6224194
ER -