Fabio Osnato

A Low Complexity Turbo MMSE Receiver for W-LAN MIMO Systems

In this paper we consider an iterative detection and decoding scheme for Space-Frequency-Bit-Interleaved Coded Modulation (SF-BICM) MIMO-OFDM systems as a candidate receiver architecture for Next Generation Wireless LANs. This work is focused on the implementation complexity reduction of the overall turbo MIMO scheme through the simplification of the three main blocks: the Soft-Interference-Canceller, the MMSE-MIMO detector and the MIMO Soft-Symbol demapper which uses extrinsic soft information, produced by a Soft-Output-Viterbi-Algorithm (SOVA), to perform the LLRs calculation of the coded bits. A new receiver architecture is proposed, its computational complexity is estimated and compared with a more classical turbo MMSE receiver, both for 16-QAM and 64-QAM constellations.

Characterization of in-home MIMO power line channels

In this paper a statistical description of in-home MIMO power line channels is derived, based on channel measurements in the 0 to 100 MHz range. In particular, it is shown that the power delay profile has a statistical distribution that could be well described by Weibull and Gaussian distributions. It is also confirmed that the channel attenuation has a linear behavior as a function of the frequency and that the average channel attenuation and the root mean square of the delay spread are inversely correlated. Furthermore, a statistical description of the MIMO power line channel coefficients is provided by using a suitable definition of the correlation among the channel coefficients. Based on the extracted statistical descriptions a new model for MIMO power line channels is proposed. Finally, the consistency between the measured and the generated power line channels is shown.

Noise correlation and its effect on capacity of inhome MIMO power line channels

In this paper we study the characteristics of in-home multi-input multi-output (MIMO) power line channels in the 0 – 100 MHz frequency band. Channel measurements are obtained in several US homes by transmitting two independent signals over two wire pairs (line-neutral and line-protective earth) and receiving on all three wire pairs (line-neutral, line-protective earth and neutral-protective earth). Noise measurements on all three wire pairs are also performed and spectral properties of noise in MIMO power line channels are presented. In particular, noise is characterized in terms of correlation among the receive ports. We analyze the effect of noise correlation on the eigenspread of the channel matrix, and also its effect on MIMO channel capacity. It is shown that while noise correlation contributes to an increase in the eigen-spread and therefore correlation of a composite channel, it ultimately improves channel capacity. The capacity of MIMO power line channels is compared for 2×2 and 2×3 MIMO configurations, showing the gain of a third receive port. Finally, capacity gains of various MIMO configurations over the single-input single-output (SISO) power line systems are provided.

Performance of Reed–Solomon codes in concatenated schemes with nonideal interleaving

The prediction of the performance of a Reed–Solomon (RS) code has an analytical solution in case of statistical independence of the errors at the input of the RS decoder (RSD). In concatenated schemes, this condition is often obtained through an interleaving device disrupting the correlation between erroneous symbols. Sometimes the ideal depth of such interleaver is too large to implement and the RSD must operate in sub-optimal conditions, for which no analytical formulas are available. In this paper, we propose a statistical model that can manage under-dimensioned interleavers. With a mild set of hypotheses on the behaviour of the inner decoder (ID), we derive analytical expressions for the performance of the concatenated code. Input data for the model can be analytical or can be obtained by simulation. We apply the method to two different types of inner codes, namely turbo codes and RS codes, and we compare the results predicted by the model with those obtained through simulation, when available, showing a very good agreement. Copyright