Error Improvement Margins for the Fluctuating Double Rayleigh with Line-of-Sight Fading Channel

The presented research demonstrated the recent advances in the problem of fading channel parameters' impact on the communication link quality. To characterize the impact, a new metric (error improvement margin) with two specific subcases is proposed. For the assumed metrics, the closed-form expressions are derived for the fluctuating double Rayleigh with shadowed line-of-sight fading channel model. The performed analytical study was followed by the numeric analysis illustrated with the quadrature amplitude modulation (QAM) (low-dimensional, i.e., 64-QAM and high-dimensional, i.e., 4096-QAM). It was demonstrated that there are several specific effects of the channel impact on the average bit error rate that can help to identify the required regimes of functioning of the systems and structures (for instance, reconfigurable intelligent surfaces), which adapt the propagation parameters for achieving the desired error rate improvement.