Recently, intermittent computing (IC) has received tremendous attention due to its high potential in perpetual sensing for Internet-of-Things (IoT). By harvesting ambient energy, battery-free devices can perform sensing intermittently without maintenance, thus significantly improving IoT sustainability. To build a practical intermittently-powered sensing system, efficient routing across battery-free devices for data delivery is essential. However, the intermittency of these devices brings new challenges, rendering existing routing protocols inapplicable. In this paper, we propose RICS, the first-of-its-kind routing scheme tailored for intermittently-powered sensing systems. RICS features two major designs, with the goal of achieving low-latency data delivery on a network built with battery-free devices. First, RICS incorporates a fast topology construction protocol for each IC node to establish a path towards the sink node with the least hop count. Second, RICS employs a low-latency message forwarding protocol, which incorporates an efficient synchronization mechanism and a novel technique called pendulum-sync to avoid the time-consuming repeated node synchronization. Our evaluation based on an implementation in OMNeT++ and comprehensive experiments with varying system settings show that RICS can achieve orders of magnitude latency reduction in data delivery compared with the baselines.

翻译：近年来，间歇计算（IC）因其在物联网（IoT）持续感知中的巨大潜力而备受关注。通过采集环境能量，无电池设备能够以维护成本为零的方式间歇性地执行感知任务，从而显著提升物联网的可持续性。为构建实用的间歇供电传感系统，实现无电池设备间高效的数据传输路由至关重要。然而，此类设备的间歇性特征带来了新的挑战，导致现有路由协议无法适用。本文提出RICS——首个专为间歇供电传感系统设计的路由方案。RICS包含两大核心设计，旨在基于无电池设备构建的网络中实现低延迟数据传输。首先，RICS集成了一种快速拓扑构建协议，使每个IC节点能以最少跳数建立至汇聚节点的路径。其次，RICS采用低延迟消息转发协议，该协议包含高效的同步机制及名为"摆锤同步"（pendulum-sync）的新技术，避免了耗时的重复节点同步过程。基于OMNeT++平台的实现评估及多系统参数下的全面实验表明：与基线方案相比，RICS可将数据传输延迟降低数个数量级。