This paper aims to exploit an orthogonal space-time block code (OSTBC) and maximal ratio combining (MRC) techniques to evaluate error rate performance of multiple-input multiple-output system for different modulation schemes operating over single- and double-Weibull fading channels.
The authors provided a novel analytical expression for cumulative distribution function (CDF) of double-Weibull distribution in the form of Meijer-G function. They also evaluated probability density function (PDF) and CDF for single- and double-Weibull random variables. CDF-based closed-form expressions of symbol error rate (SER) are computed for the proposed systems’ design.
Based on simulation and analytical results, the authors have shown that double-Weibull fading which shows the cascaded nature of channel gives significantly poor SER performance compared to that of single-Weibull fading. Moreover, MRC offers an improved error rate performance compared to that of OSTBC. As the fading parameter increases for any modulation technique, the required signal-to-noise ratio (SNR) gap between single- and double-Weibull fading decreases. Finally, it is observed that the analytical results are a good approximation to simulation results.
For practical implication, the authors use a number of antennas at the base station, but solely to maximize performance, one can use receive diversity, i.e. MRC.
Using higher-order modulation (i.e. 16-QAM), 4 and 1 dB less SNR is required at high and less fading, respectively, in single-Weibull fading as compared to double-Weibull fading. Hence, at higher-order modulation, double-Weibull channel model performs better as compared to lower-order modulation.
