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For a space-time coded system subject to flat Rayleigh fading, we formulate the pairwise error probability (PEP) in a unified expression, which accounts for the cases of perfect channel-state information, imperfect channel estimation, and unknown channel. The unified PEP expression is then bounded by an exponential-type inequality leading to a tight upper bound on the PEP. The bound indicates that to design a good code set, we not only need to maximize the geometric mean of the nonzero eigenvalues of the code difference matrix, but also minimize their harmonic mean. [ABSTRACT FROM PUBLISHER]

We consider a complex-valued L times L square matrix whose diagonal elements are unity, and lower and upper diagonal elements are the same, each lower diagonal element being equal to a (a ne 1) and each upper diagonal element being equal to b (b ne 1). We call this matrix the generalized semiuniform matrix, and denote it as M(a, b,L). For this matrix, we derive closed-form expressions for the characteristic polynomial, eigenvalues, eigenvectors, and inverse. Treating the non-real-valued uniform correlation matrix M(a, a*, L), where (middot)* denotes the complex conjugate and a ne a*, as a Hermitian generalized semiuniform matrix, we obtain the eigenvalues, eigenvectors, and inverse of M(a, a*, L) in closed form. We present applications of these results to the analysis of communication systems using diversity under correlated fading conditions [ABSTRACT FROM PUBLISHER]

We derive closed-form expressions for the single-user capacity of maximal ratio combining diversity systems taking into account the effect of correlation between the different branches. We consider a Rayleigh fading channel with two kinds of correlation: 1) equal branch signal-to-noise ratios (SNRs) and the same correlation between any pair of branches and 2) unequal branch SNRs and arbitrary correlation between branches such that the eigenvalues of the branch covariance matrix are all distinct. Three adaptive transmission schemes are analyzed: 1) optimal simultaneous power and rate adaptation; 2) optimal rate adaptation with constant transmit power; and 3) channel inversion with fixed rate. [ABSTRACT FROM PUBLISHER]

We derive an exact bit-error probability (BEP) expression for coherent detection of binary signals with optimum combining in wireless systems in the presence of multiple cochannel interferers and thermal noise. A flat Rayleigh fading environment with space diversity, uncorrelated equal-power interferers, and additive white Gaussian noise is considered. The approach is to use the chain rule of conditional expectation together with the joint probability density function (pdf) of the eigenvalues of the interference correlation matrix. This joint pdf is related to the Vandermonde determinant. Let NA denote the number of antennas and NI the number of interferers. We consider both the cases of an overloaded system, in which NI≥NA, and an underloaded system, in which NI