On Asymptotics of Eigenvectors of Large Sample Covariance Matrix

Let $\{X_{ij}\}$, i, j =..., be a double array of i.i.d. complex random variables with EX₁₁ = 0, E|X₁₁|² = 1 and E|X₁₁|⁴ < ∞, and let $A_{n}=\frac{1}{N}T_{n}^{1/2}X_{n}X_{n}^{\ast }T_{n}^{1/2}$, where $T_{n}^{1/2}$ is the square root of a nonnegative definite matrix $T_{n}$ and $X_{n}$ is the...

Ausführliche Beschreibung

Bibliographische Detailangaben
Veröffentlicht in:The Annals of Probability. - Institute of Mathematical Statistics. - 35(2007), 4, Seite 1532-1572
1. Verfasser: Bai, Z. D. (VerfasserIn)
Weitere Verfasser: Miao, B. Q., Pan, G. M.
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2007
Zugriff auf das übergeordnete Werk:The Annals of Probability
Schlagworte:Asymptotic distribution Central limit theorems CDMA Eigenvectors and eigenvalues Empirical spectral distribution function Haar distribution MIMO Random matrix theory Sample covariance matrix SIR mehr... Stieltjes transform Strong convergence Mathematics Information science
Beschreibung
Zusammenfassung:Let $\{X_{ij}\}$, i, j =..., be a double array of i.i.d. complex random variables with EX₁₁ = 0, E|X₁₁|² = 1 and E|X₁₁|⁴ < ∞, and let $A_{n}=\frac{1}{N}T_{n}^{1/2}X_{n}X_{n}^{\ast }T_{n}^{1/2}$, where $T_{n}^{1/2}$ is the square root of a nonnegative definite matrix $T_{n}$ and $X_{n}$ is the n × N matrix of the upper-left corner of the double array. The matrix $A_{n}$ can be considered as a sample covariance matrix of an i.i.d. sample from a population with mean zero and covariance matrix $T_{n}$, or as a multivariate F matrix if $T_{n}$ is the inverse of another sample covariance matrix. To investigate the limiting behavior of the eigenvectors of $A_{n}$, a new form of empirical spectral distribution is defined with weights defined by eigenvectors and it is then shown that this has the same limiting spectral distribution as the empirical spectral distribution defined by equal weights. Moreover, if $\{X_{ij}\}$ and $T_{n}$ are either real or complex and some additional moment assumptions are made then linear spectral statistics defined by the eigenvectors of $A_{n}$ are proved to have Gaussian limits, which suggests that the eigenvector matrix of $A_{n}$ is nearly Haar distributed when $T_{n}$ is a multiple of the identity matrix, an easy consequence for a Wishart matrix.
ISSN:00911798