Several proofs of the monotonicity of the nonGaussianness (divergence with respect to a Gaussian random variable with identical second order statistics) of the sum of n independent and identically distributed (i.i.d.) random variables were published. We give an upper bound on the decrease rate of the non-Gaussianness which is proportional to the inverse of n, for large n. The proof is based on ...

Multipath channels often exhibit sparse structures in multicarrier underwater acoustic (MC-UWA) communication systems. Conventional linear channel estimators, such as least squares (LS) and minimum mean square error (MMSE) are considered as optimal solutions under the assumption of rich multipath. However, they often result in low spectral efficiency due to neglect of the sparsity in multipath ...

Blind fractionally spaced equalizers reduce intersymbol interference using second-order statistics without the need for training sequences. Methods for finding FIR zero-forcing blind equalizers directly from the observations are described, and adaptive versions are developed. In contrast, most current methods require channel estimation as a first step to estimating the equalizer. The direct met...

A multi-input multi-output (MIMO) communication system combined with orthogonal frequency division multiplexing (OFDM) system can provide high transmission data rate, spectral efficiency and reliability for wireless communication systems. These parameters can be further improved by combating with fading, the effect of which can be reduced by properly estimating the channel at the receiver side....

Traditional subspace based speech enhancement (SSE) methods use linear minimum mean square error (LMMSE) estimation that is optimal if the Karhunen Loeve transform (KLT) coefficients of speech and noise are Gaussian distributed. In this paper, we investigate the use of Gaussian mixture (GM) density for modeling the non-Gaussian statistics of the clean speech KLT coefficients. Using Gaussian mix...

DS-CDMA can achieve good bit error rate (BER) performance in a severe frequency-selective fading channel by using frequency-domain equalization (FDE) based on MMSE criterion instead of rake combining. FDE requires accurate channel estimation (CE). Recently, a decision feedback (DF)MMSE-CE using a fixed DF filter coefficient has been proposed. The DF filter coefficient is an important design par...

Multiple-input multiple-output (MIMO) multiplexing is an attractive technique to achieve very high-speed transmission with a limited bandwidth. Recently, we proposed an iterative frequency-domain interference cancellation (FDIC) for single-carrier MIMO (SC-MIMO) multiplexing. In our previous work, assuming that the interference from the other antennas can be perfectly cancelled in FDIC, one-dim...

This paper provides upper and lower bounds on the information rates achievable with a minimum mean square error (MMSE) Tomlinson-Harashima precoder (THP) assuming ideal interleaving. We also give an exact formula for zero-forcing (ZF) THP achievable information rates. At high SNR, the performance of the MMSE-THP and the ZF-THP identically suuer only the 2.55 bit or 1.53 dB \shaping" loss from c...

We derive a simple general parametric representation of the rate–distortion function of a memoryless source, where both the rate and the distortion are given by integrals whose integrands include the minimum mean square error (MMSE) of the distortion ∆ = d(X, Y ) based on the source symbol X , with respect to a certain joint distribution of these two random variables. At first glance, these rel...

In this paper, we explore Code Division Multiple Access (CDMA) systems with multiple transmit and receive antennas combined with Space-Time Trellis Codes over a frequency selective channel. The conventional multi-user Minimum Mean Square Error (MMSE) detector is generalized to deal with multiple antennas and multiple paths and, then, extended to include the turbo principle in an iterative fashi...