Impact of fading correlations on MIMO communication systems in geometry-based statistical channel models

Abstract

This paper highlights the impact of channel correlations on the capacity and performance of MIMO communications, with a focus on the so-called diagonal correlations. Based on this analysis, the limitations of simplified mathematical representations, such as the Kronecker or the diagonal-decorrelation models, are pointed out. Finally, the correlation properties of popular geometry-based statistical models are studied in order to analyze whether the correlation structure of these models can be adequately represented by simplified mathematical models, as well as to quantify the errors introduced by these simplifications. With respect to channel correlations, neither the Kronecker nor the diagonal-decorrelation assumptions are good representations of the correlation structure of the investigated geometry-based statistical models. When comparing capacity and symbol error probability results, it is found that the diagonal-decorrelation model may yield significant errors on both considered metrics. The Kronecker model generally yields errors less than one order of magnitude on the symbol error rate, but relative errors on ergodic or outage capacity may be more significant.

Estimating Combined Correlation Functions for Dipoles in Rayleigh-Fading Scenarios

“…Else, the combined correlation would increase instead of the expected decrease since nonidentical orientations are used. Consequently, we propose a linear model which merges the spatial distance with its equivalent distance for angular diversity in a linear manner by (6) where . In Fig.…”

“…When the correlation occurs only at either the receiver or transmitter ends, but not at both, the model is known as semicorrelated [4]. Some other models with cross-correlation assumptions are also available [5], including some analyses of the capacity and symbol error rate errors [6]. Some recent studies, however, claim that in order to obtain a good estimation of MIMO performance, it is essential to consider the relationship between transmit and receive antennas [7].…”

On the MIMO Channel Capacity Predicted by Kronecker and Müller Models

“…This model is reported to fail in predicting the MIMO system performance under certain circumstances and to be more accurate in channels with low fading correlations [8], [9].…”

Some Remarkable Properties of Diagonally Correlated MIMO Channels

“…It was recently shown in [2] and [3] that a simple mutual information metric equal to E{κ} allows for analysis of ergodic MIMO capacity as a function of the correlations between different channel matrix elements. A most surprising result was that ergodic mutual information and capacity 1 are not maximized by i.i.d.…”