Diffusive molecular communication (DMC), in which molecules are used to deliver information in diffusion channel, is one of the most prominent systems in nanonetworks. In particular, the research on end-to-end mobile DMC system is even more challenging. In this paper, we investigate the energy efficiency of multi-hop mobile DMC system. First, the energy model for this system is proposed based on the mobilities of transmitter nanomachine (TN), relays and receiver nanomachine (RN). Then the mathematical expressions of total energy consumption and throughput are derived. Furthermore, the energy efficiency which is defined as the throughput per unit energy consumption is analyzed. Finally, the numerical results show that the parameters including the diffusion coefficients and velocities of mobile TN, relays and RN, the initial distance of each hop, the number of molecules emitted in each time slot by TN and relays, and each time slot duration have different impacts on the energy efficiency. How to set these system parameters can be used to provide guidelines for designing energy efficient multi-hop mobile DMC system.

扩散分子通信（DMC）是纳米网络中最著名的系统之一，其中分子被用来在扩散通道中传递信息。特别是，对端到端移动DMC系统的研究更具挑战性。在本文中，我们研究了多跳移动DMC系统的能效。首先，基于发射器纳米机（TN），中继器和接收器纳米机（RN）的迁移率，提出了该系统的能量模型。然后推导了总能耗和吞吐量的数学表达式。此外，分析了定义为每单位能耗的吞吐量的能效。最后，数值结果表明，参数包括移动TN，中继和RN的扩散系数和速度，每跳的初始距离，TN和中继在每个时隙中发射的分子数量，以及每个时隙持续时间对能量效率的影响都不同。如何设置这些系统参数可为设计节能多跳移动DMC系统提供指导。