The recently introduced independent fluctuating two-ray (IFTR) fading model, consisting of two specular components fluctuating independently plus a diffuse component, has proven to provide an excellent fit to different wireless environments, including the millimeter-wave band. However, the original formulations of the probability density function (PDF) and cumulative distribution function (CDF) of this model are not applicable to all possible values of its defining parameters, and are given in terms of multifold generalized hypergeometric functions, which prevents their widespread use for the derivation of performance metric expressions. In this paper we present a new formulation of the IFTR model as a countable mixture of Gamma distributions which greatly facilitates the performance evaluation for this model in terms of the metrics already known for the much simpler and widely used Nakagami-m fading. Additionally, a closed-form expression is presented for the generalized moment generating function (GMGF), which permits to readily obtain all the moments of the distribution of the model, as well as several relevant performance metrics. Based on these new derivations, the IFTR model is evaluated for the average channel capacity, the outage probability with and without co-channel interference, and the bit error rate (BER), which are verified by Monte Carlo simulations.

翻译：最近提出的独立双射线(IFTR)衰落模型由两个独立波动的镜面分量和一个漫射分量组成，已被证明能够出色地拟合包括毫米波波段在内的不同无线环境。然而，该模型概率密度函数(PDF)和累积分布函数(CDF)的原始表达式不适用于其定义参数的所有可能取值，并且以多重广义超几何函数形式给出，这阻碍了其在性能指标推导中的广泛使用。本文提出了一种将IFTR模型表示为伽马分布可数混合的新形式，极大地促进了基于更简单且广泛使用的Nakagami-m衰落已知指标对该模型的性能评估。此外，我们给出了广义矩生成函数(GMGF)的闭式表达式，该表达式可方便地获得模型分布的所有矩以及若干相关性能指标。基于这些新推导，我们对IFTR模型评估了平均信道容量、有/无同频干扰时的中断概率以及误码率(BER)，并通过蒙特卡洛仿真进行了验证。