The Industrial Internet of Things (IIoT) paradigm has emerged as a transformative force, revolutionizing industrial processes by integrating advanced wireless technologies into traditional procedures to enhance their efficiency. The importance of this paradigm shift has produced a massive, yet heterogeneous, proliferation of scientific contributions. However, these works lack a standardized and cohesive characterization of the IIoT framework coming from different entities, like the 3rd Generation Partnership Project (3GPP) or the 5G Alliance for Connected Industries and Automation (5G-ACIA), resulting in divergent perspectives and potentially hindering interoperability. To bridge this gap, this article offers a unified characterization of (i) the main IIoT application domains, (ii) their respective requirements, (iii) the principal technological gaps existing in the current literature, and, most importantly, (iv) we propose a systematic approach for assessing and addressing the identified research challenges. Therefore, this article serves as a roadmap for future research endeavors, promoting a unified vision of the IIoT paradigm and fostering collaborative efforts to advance the field.

翻译：工业物联网（IIoT）范式已成为一股变革性力量，通过将先进无线技术融入传统流程以提升其效率，从而革新了工业过程。这一范式转变的重要性催生了大量但异质性的科研成果涌现。然而，这些来自不同实体（如第三代合作伙伴计划（3GPP）或5G互联产业与自动化联盟（5G-ACIA））的研究工作缺乏对IIoT框架标准化且连贯一致的描述，导致观点分歧并可能阻碍互操作性。为弥合这一差距，本文提供了以下方面的统一描述：（i）主要的IIoT应用领域，（ii）其各自的需求，（iii）现有文献中的主要技术差距，并且最重要的是，（iv）我们提出了一种系统性方法来评估和应对已识别的研究挑战。因此，本文可作为未来研究工作的路线图，推动对IIoT范式的统一认识，并促进协作努力以推动该领域发展。