Molecular communications is a technique emulated by researchers, which has already been used by the nature for millions of years. In Molecular Communications via Diffusion (MCvD), messenger molecules are emitted by a transmitter and propagate in the fluidic environment in a random manner. In biological systems, the environment can be considered a bounded space, surrounded by different structures, such as tissues and organs. The propagation of molecules is affected by these structures in the environment, which reflect the molecules upon collision. Hence, understanding the behavior of MCvD systems near reflecting surfaces is important for modeling molecular communication systems analytically. However, deriving the channel response of MCvD systems with an absorbing spherical receiver requires solving the diffusion equation in 3-D space in the presence of a reflecting boundary, which is extremely challenging. Therefore, derivation of the channel response in a bounded environment has remained one of the unanswered questions in the literature. In this paper, a method to model molecular communication systems near reflecting surfaces is proposed, and an analytical closed-form solution for the channel response is derived.

翻译：分子通信是一种被研究人员模仿的技术，而自然界已将其运用了数百万年。在基于扩散的分子通信中，信使分子由发射器释放，并在流体环境中以随机方式传播。在生物系统中，环境可视为由不同结构（如组织和器官）包围的有限空间。环境中这些结构会影响分子传播，当分子与之碰撞时会发生反射。因此，理解反射表面附近分子通信系统的行为对于解析建模分子通信系统至关重要。然而，推导具有吸收球状接收器的分子通信系统信道响应，需要在存在反射边界的三维空间中求解扩散方程，这极具挑战性。因此，有界环境中的信道响应推导一直是文献中尚未解决的难题之一。本文提出了一种对反射表面附近分子通信系统进行建模的方法，并推导了信道响应的解析闭式解。