Low-SNR Analysis of MIMO Weibull Fading Channels

The capacity performance of multiple-input multiple-output (MIMO) systems in Weibull fading channels has not been properly addressed in the literature. In this paper, we consider three MIMO architectures, namely spatial-multiplexing (SM) MIMO systems with optimal and minimum mean square error (MMSE) receivers as well as orthogonal space-time block-codes (OSTBC) MIMO systems, that operate over Weibull fading channels. Since the capacity analysis at arbitrary Signal-to-Noise ratios (SNRs) is intractable, we focus on the low-SNR regime which is characterized by the minimum energy per information bit to reliably convey any positive rate and the wideband slope. For these two metrics, new closed-form expressions are derived which enable us to perform a detailed comparative study of the considered configurations and assess MIMO capacity in Weibull fading channels.