This article presents new expressions for the bit error probability (BEP) of the M-ary quadrature amplitude modulation (M-QAM) and rectangular QAM (R-QAM) scheme in a frequency non-selective channel model with cascaded double fading, characterized in the links by the distributions η-μ, κ-μ or α-μ. In this paper, the probability density function (PDF) of the signal-to-noise ratio (SNR) of the double link is written in terms of an integral of the product of the PDF of the envelope of the first link by the PDF of the SNR of the second link. With this procedure, expressions for the BEP of the M-QAM and R-QAM scheme, with and without a maximum ratio combiner (MRC) associated, are obtained by means of the general expressions of Cho and Yoon, calculated with the help of the Gauss-Laguerre quadrature. The new expressions are written in terms of the integral of the moment generating function (MGF) of the instantaneous SNR from the second link, which are simpler than using expressions involving infinite series in terms of special functions like hypergeometric functions and the Meijer G-function. In addition, insights regarding the expressions obtained and comments about their complexity are provided. Several curves for the BEP are presented, for different parameters that characterize the channel and different numbers of branches of the MRC. All analytical expressions obtained in this paper are corroborated by computer simulations performed with the Monte Carlo method.

本文为具有级联双衰落的频率非选择性信道模型中的M元正交幅度调制（M-QAM）和矩形QAM（R-QAM）方案的误码概率（BEP）提供了新的表达式，其特征在于通过η - μ，κ - μ或α - μ的分布。在本文中，双链路的信噪比（SNR）的概率密度函数（PDF）用第一链路的包络的PDF乘以PDF的乘积的积分来表示。第二条链路的SNR。通过此过程，借助Cho和Yoon的通用表达式，可以借助M和QAM方案的BEP表达式，并结合使用和不使用最大比率合并器（MRC）来获得M-QAM和R-QAM方案的BEP表达式。高斯-拉格瑞正交。根据来自第二个链接的瞬时SNR的矩生成函数（MGF）的积分来编写新表达式，这比使用涉及无限级数的表达式（如超几何函数和Meijer G函数）更简单。此外，提供了有关所获得表达式的见解以及对其复杂性的注释。给出了BEP的几条曲线，分别针对表征信道和MRC分支数量不同的参数。本文获得的所有分析表达式均通过使用Monte Carlo方法进行的计算机模拟得到了证实。