Molecular Communication via Diffusion (MCvD) is a prominent small-scale technology, which roots from the nature. With solid analytical foundations on channel response and advanced modulation techniques, molecular single-input-single-output (SISO) systems are one of the most studied molecular networks in the literature. However, the literature is yet to provide sufficient analytical channel modeling on molecular multiple-output systems with fully absorbing receivers, {one of the common applications in the area. In this paper, a channel model for molecular single-input-multiple-output (SIMO) systems is proposed for estimating the channel response of such systems. With the model's recursive nature, the closed-form solution of the channel response of molecular 2-Rx SIMO systems is analytically derived. A simplified model with lower complexity is also presented at a cost of slightly less accurate channel estimation. The models are extended to the molecular SIMO systems with more than two receivers. The performance of the methods are evaluated for several topologies with different parameters, and the accuracy of the model is verified by comparing to computer-simulated channel estimations in terms of quantitative error metrics such as root-mean-squared error. The performance of the simplified model is verified by the amount of deviation, indicating sufficient channel modeling performance with reduced computational power.

翻译：基于扩散的分子通信（MCvD）是一种源于自然的重要小尺度技术。凭借信道响应方面扎实的分析基础以及先进的调制技术，分子单输入单输出（SISO）系统是文献中研究最为广泛的分子网络之一。然而，现有文献尚未为带有完全吸收接收器的分子多输出系统提供充分的分析性信道建模，而这类系统是该领域的常见应用之一。本文提出了一种分子单输入多输出（SIMO）系统的信道模型，用于估计此类系统的信道响应。利用该模型的递归特性，解析推导了具有两个接收器的分子SIMO系统信道响应的闭式解。此外，还提出了一种复杂度较低的简化模型，尽管该模型会略降低信道估计的准确性。这些模型进一步扩展至具有两个以上接收器的分子SIMO系统。通过不同参数下的多种拓扑结构评估了方法的性能，并基于均方根误差等定量误差指标，将模型与计算机模拟的信道估计结果进行了对比，验证了模型的准确性。简化模型的性能通过偏差量进行了验证，表明其在降低计算能力需求的同时，仍能保持良好的信道建模性能。