Energy consumption is a major challenge in IoT devices, which was aimed to be improved by employing energy-efficient objective functions (OFs) in the structure of the RPL routing protocol. Meanwhile, the majority of the existing OFs mainly perform the parent selection based on the gathered information from the routing layer. Nevertheless, based on our investigations, there exists a series of transmission operations in the medium access control (MAC) layer, which significantly affects the energy consumption in IoT devices. Therefore, in this article, we propose ELITE, an energy-efficient cross-layer OF, which introduces a novel routing metric, called strobe per packet ratio (SPR). SPR indicates the number of transmitted strobes per packet due to radio duty cycling (RDC) policies in the MAC layer. This newly defined metric, which has been designed to be coupled with asynchronous MAC protocols, could be differentiated node by node and based on the existing relative phase shift between the communicating nodes. In this regard, the ELITE tries to select a path, which imposes less number of strobe transmissions to its nodes. According to the evaluation results, while ELITE could reduce the average amount of required strobes per packet by up to 25%, it can significantly improve the average amount of consumed energy in an IoT node by up to 39% compared to its counterpart OFs.

中文翻译：

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ELITE：精心设计的跨层RPL目标功能，可在物联网设备中实现能源效率

能耗是物联网设备中的主要挑战，旨在通过在RPL路由协议的结构中采用节能目标函数（OF）来改善能耗。同时，大多数现有的OF主要基于从路由层收集的信息来执行父选择。但是，根据我们的调查，在媒体访问控制（MAC）层中存在一系列传输操作，这极大地影响了IoT设备的能耗。因此，在本文中，我们提出了一种节能的跨层OF ELITE，它引入了一种新颖的路由度量，称为每包频闪比（SPR）。SPR表示由于MAC层中的无线电占空比（RDC）策略而导致每个数据包传输的选通脉冲数。这个新定义的指标 可以将其设计为与异步MAC协议耦合，并且可以根据通信节点之间现有的相对相移，逐个节点地对其进行区分。在这方面，ELITE尝试选择一条路径，该路径会向其节点施加较少数量的选通传输。根据评估结果，尽管ELITE可以将每个数据包平均所需的选通脉冲数量减少多达25％，但与同类OF相比，它可以显着提高IoT节点中的平均平均能耗，最多可以提高39％。