X

Matrix X (boldface capital letter)

x

Vector x (boldface lowercase letter)

[X] _i,j

The element on row i and column j of matrix X

X ^T

Transpose of X

X*

Conjugate transpose of X

det (X)

Determinant of X

tr (X)

Trace of X

X _F

Frobenius norm of X

? (X)

Eigenvalues of X

? _X

The diagonal matrix of the eigenvalues of the Hermitian matrix X

? _X

The diagonal matrix of the singular values of X

U _X

The eigen- or singular-vector matrix of X

X is positive semi-definite

vec (X)

Vectorize X into a vector by concatenating the columns of X

Kronecker product

I

An identity matrix

E[ ]

Expected value

(x) ₊

M _T

The number of transmit antennas

M _R

The number of receive antennas

H

A MIMO flat-fading channel

H _w

A random channel with i.i.d. zero-mean complex Gaussian elements

H _m

The channel mean

R

A covariance of the channel

R _t

Transmit covariance, also called the transmit antenna correlation

R _r

Receive covariance, also called the receive antenna correlation

K

The Ricean K factor

T _c

The channel coherence time

B _c

The channel coherence bandwidth

D _c

The channel coherence distance

(t)

At time or delay t

?

Channel temporal correlation function

F

The precoding matrix

p _i

Power loading on beam i

C

A codeword

Q

The codeword covariance matrix

A

The codeword difference product...