A three-dimensional (3-D) diffusive mobile-molecular communication system is considered inside the unbounded environment. We consider a point transmitter and a perfectly absorbing spherical receiver which can move randomly in any of the three coordinates. The closed-form expression for expected hitting rate for 3-D unbounded communication channel with nanomachines mobility is derived. The performance of considered system is further evaluated in terms of probability of detection ($P_D$), probability of false alarm ($P_{FA}$), and probability of error ($P_e$). The system is further analyzed in terms of average mutual information and average maximum achievable rate. Furthermore, an optimum decision threshold, at which minimum probability of error and maximum information rate occur is also derived. The analytical results are verified through particle-based and Monte-Carlo simulations.

在无界环境中考虑了三维（3-D）扩散移动分子通信系统。我们考虑了一个点发射器和一个完美吸收的球形接收器，它们可以在三个坐标中的任何一个中随机移动。推导了具有纳米机械运动性的3-D无界通信通道的预期命中率的闭式表达式。考虑到的系统的性能将根据检测概率进一步评估（$P_d$），误报的可能性（$P_{F\mathrm{一种}}$）和错误概率（$P_{Ë}$）。根据平均互信息和平均最大可实现速率进一步分析了该系统。此外，还导出了最佳决策阈值，在该最优决策阈值处发生最小错误的可能性和最大信息率。通过基于粒子的模拟和蒙特卡洛模拟验证了分析结果。