The Internet of Things (IoT) technology uses small and cost-effective sensors for various applications, such as Industrial IoT. However, these sensor nodes are powered by fixed-size batteries, which creates a trade-off between network performance and long-term sustainability. Moreover, some applications require the network to provide a certain level of service, such as a lower delay for critical data, while ensuring the operational reliability of sensor nodes. To address this energy challenge, external energy harvesting sources, such as solar and wind, offer promising and eco-friendly solutions. However, the available energy from a single energy source is insufficient to meet these requirements. This drives the utilization of a hybrid energy harvesting approach, such as the integration of solar and wind energy harvesters, to increase the amount of harvested energy. Nevertheless, to fully utilize the available energy, which is dynamic in nature, the sensor node must adapt its operation to ensure sustainable operation and enhanced network performance. Therefore, this paper proposes a hybrid energy harvesting-based energy neutral operation (ENO) medium access control (MAC) protocol, called HENO-MAC, that allows the receiver node to harvest energy from the solar-wind harvesters and adapt its duty cycle accordingly. The performance of the proposed HENO-MAC was evaluated using the latest realistic solar and wind data for two consecutive days in GreenCastalia. The simulation results demonstrate that the duty cycle mechanism of HENO-MAC effectively utilizes the harvested energy to achieve ENO and uses the available energy resources efficiently to reduce the packet delay for all packets and the highest priority packet by up to 28.5% and 27.3%, respectively, when compared with other existing MAC protocols.

翻译：物联网技术采用小型、经济高效的传感器应用于工业物联网等场景。然而，这些传感器节点由固定容量的电池供电，这在网络性能与长期可持续性之间形成了权衡。同时，某些应用要求网络在保障传感器节点运行可靠性的前提下提供特定服务质量，例如降低关键数据的传输延迟。为应对这一能量挑战，太阳能、风能等外部能量采集方案提供了极具前景的环保解决方案。但单一能量源的可采集能量难以满足上述需求，这促使研究人员采用混合能量采集方法（如集成太阳能与风能采集器）来增加能量获取总量。然而，为充分利用具有动态特性的可用能量，传感器节点必须自适应调整其运行策略以实现可持续运作并提升网络性能。为此，本文提出一种基于混合能量采集的能量中性运行（ENO）介质访问控制（MAC）协议——HENO-MAC，该协议使接收节点能够从太阳能-风能混合采集器中获取能量，并据此动态调整其占空比。利用GreenCastalia平台中连续两天的真实太阳能与风能最新数据对HENO-MAC性能进行评估。仿真结果表明，与其他现有MAC协议相比，HENO-MAC的占空比机制能够有效利用采集能量实现ENO状态，并高效分配可用能量资源，使所有数据包及最高优先级数据包的延迟分别降低高达28.5%和27.3%。