Signal processing method and apparatus for obtaining diversity gain in wireless communication system equipping antenna array

A signal processing method for obtaining a diversity gain in a communication system equipping an antenna array when a background noise is a spatial white noise vector, comprising the steps of:

• a) calculating a covariance matrix of an input signal vector defined according to an equation as
• 13 R ^ y = 1 N ⁢ ∑ l = 0 N - 1 ⁢ y ⁡ [ l ] ⁢ y H ⁡ [ l ] ,
• wherein N is a smoothing factor;
• b) performing a eigen-division of the covariance matrix and estimating plural number (r) of time invariance vectors ({em});
• c) calculating an instance coefficient ĥm[l] of a pre-known pilot signal s[l] by accumulating an eigenvector and an input signal vector according to an equation as ĥm[l]=êmHy[l]s*[l] (m=1,2, . . . ,r) and estimating the channel coefficients {overscore (hm)}[l](m=1,2, . . . ,r) in a channel coefficient estimating means by using the instant coefficient, wherein y[l] is the pilot vector and s[l] is a pilot signal;
• and
• d) estimating a channel vector by using the channel coefficient computed in the step c) and the eigenvector corresponding to the eigenvalue of the input signal vector based on an equation as
• 14 h ^ ⁡ [ l ] = ∑ k = 1 r ⁢ h k _ ⁡ [ l ] ⁢ e ^ k .

A signal processing method for obtaining a diversity gain in a communication system equipping an antenna array when a background noise is a non-white noise, comprising the steps of:

• a) transforming the non-white noise of an input signal to a white noise;
• b) calculating a covariance matrix of the white noise;
• c) performing an eigen-division of the covariance matrix and estimating a time invariance vector forming a signal sub-space according to a matrix rank (r) of the covariance by selecting at least two eigenvectors, which have comparatively larger value, among the eigenvectors corresponding each eigenvalue of the covariance matrix;
• and
• d) estimating a channel vector by receiving the time invariance vector from the step b) and a channel coefficient computed by using a pre-known symbol.

A signal processing method for obtaining a diversity gain in a communication system equipping an antenna array when a background noise is a non-white noise vector, comprising the steps of:

• a) estimating the covariance matrix of the non-white noise of an input signal, performing a matrix factorization and transforming to a white noise after performing the matrix factorization based on an equation as z[l]=(VH)−1y[l];
• b) calculating the covariance matrix based on z[l] according to an equation as
• 16 R ^ z = 1 N ⁢ ∑ l = 0 N - 1 ⁢ z ⁡ [ l ] ⁢ z H ⁡ [ l ] ;
• c) performing an eigen-division of the covariance matrix and estimating plural number (r) of time invariance vectors ûm (m=1,2, . . . ,L,)forming a signal sub-space based on a matrix rank (r);
• d) calculating an instant coefficient by accumulating the eigenvector of the pre-known pilot signal s[l] and the input signal vector according to an equation as ĝm[l]=umHz[{circumflex over (l)}]s*[l] (m=1,2, . . . ,r), wherein s[l] is the pilot signal and z[l] is the input signal vector, which is transformed to the white noise;
• e) estimating a channel coefficient {overscore (gm)}[l] (m=1,2, . . . ,r) based on the instant coefficient;
• and
• f) estimating a channel vector by using the channel coefficient {overscore (gm)}[l] (m=1,2, . . . ,r) computed in the step c) and the eigenvector ûm (m=1,2, . . . ,L) corresponding to the eigenvalue of the input signal vector, which is transformed to the white noise based on an equation as
• 17 g ^ ⁡ [ l ] = ∑ m = 1 r ⁢ g m _ ⁡ [ l ] ⁢ u ^ m .

A signal processing apparatus for obtaining a diversity gain in a communication system equipping an antenna array when a background noise is a spatial white noise vector, comprising:

• a) covariance matrix estimating means for obtaining an input signal vector by sampling a baseband signal of an input signal, which is received through a plurality of antenna elements, and calculating a covariance matrix of the input signal vector;
• b) eigenvalue division means for performing an eigen-division of the covariance matrix;
• c) eigenvector estimating means for estimating a time invariance vector forming a signal sub-space according to a matrix rank (r) of the covariance matrix by selecting at least two eigenvectors having comparatively larger eigenvalues;
• d) channel vector estimating means for estimating a channel vector by receiving the time invariance vector and the channel coefficient computed by using the pre-known symbol;
• and
• e) calculating means for outputting a beam-forming vector by adding weight values of the channel vector.

A signal processing apparatus for obtaining a diversity gain in a communication system equipping an antenna array when a background noise is a non-white noise vector, comprising:

• a) covariance matrix estimating means for obtaining a input signal vector of a non-white noise by sampling baseband signals of input signals received through a plurality of antenna elements, transforming the non-white noise to a white noise and calculating a covariance matrix of the white noise;
• b) eigenvalue division means for performing an eigen-division of the covariance matrix;
• c) eigenvector estimating means for estimating a time invariance vector forming a signal sub-space according to a matrix rank (r) of the covariance matrix by selecting at least two larger eigenvectors corresponding to each eigenvalue of the covariance matrix;
• d) channel vector estimating means for estimating a channel vector by receiving the time invariance vector and the channel coefficient computed by using the pre-known symbol;
• and
• e) calculating means for outputting a beam-forming vector by adding weight values of the channel vector.

A computer readable recording medium storing instructions for executing the signal processing method in case of that a background noise is a space white noise vector, comprising the functions of:

• a) computing a covariance matrix of an input signal vector;
• b) performing a eigen-division of the covariance matrix and estimating a time invariance vector forming a signal sub-space according to a matrix rank (r) of the covariance by selecting at least two eigenvectors, which have comparatively larger valued among the eigenvalues corresponding eigenvectors of the covariance matrix;
• c) estimating a channel vector by receiving the time invariance vector from the step b) and a channel coefficient computed by using a pre-known symbol;
• and
• d) outputting a beam-forming vector by adding weights of the channel vectors from the step c).

A computer readable recording medium storing instructions for executing the signal processing method in case of that a background noise is a non-white noise vector, comprising the functions of:

• a) transforming the non-white noise of an input signal to a white noise;
• b) calculating a covariance matrix of the white noise;
• c) performing a eigen-division of the covariance matrix and estimating time invariance vectors forming a signal sub-space according to a matrix rank (r) of the covariance by selecting at least two eigenvectors, which have comparatively larger value, among the eigenvalues corresponding eigenvectors of the covariance matrix;
• and
• d) estimating a channel vector by receiving the time invariance vector from the step b) and a channel coefficient computed by using a pre-known symbol.