Fundamentals of Acute Relay CSI Severity
Khoa Nguyen Le · IEEE Transactions on Wireless Communications · 2020
A probability density function (pdf) of bivariate exponential-correlated (exp.c.) Rayleigh fading-the simplest under correlated fading-has chronically been employed to model decode-and-forward relay networks under outdated channel state information (CSI) conditions. !n addition to CSI outdatedness, CSI imperfection exists, however, their compound co-modelling-defined as acute imperfect CSI-outdated CSI- has not yet been performed in the existing literature. Using a joint pdf of trivariate exp.c. Nakagami-m fading-which is more advanced than the pdf of bivariate exp.c. Rayleigh fading-this article models acute imperfect CSI-outdated CSI, and examines its impact on relay networks. Selection combining (SC) is also employed to improve the practicality of this work. Using a pdf of bivariate exp.c. Nakagami-m fading, conditional pdfs of relay SNRs under acute-CSI severity are derived. Using the newlyderived conditional functions, pdfs of Rayleigh fading for SC deployment under acute imperfect CSI-outdated CSI severity are then obtained. Ergodic channel capacity, diversity gains, averageSNR gains, and outage probability are then computed to (a) obtain insight into the proposed findings, and (b) examine the impact of acute-CSI conditions on network performance. Existing results are employed for clarification purposes, and to show the advantage of the proposed work. Monte Carlo simulation is given, which matches theoretical predictions.