Medium access in 5G systems was tailored to accommodate diverse traffic classes through network resource slicing. 6G wireless systems are expected to be significantly reliant on Artificial Intelligence (AI), leading to data-driven and goal-oriented communication. This leads to augmentation of the design space for Medium Access Control (MAC) protocols, which is the focus of this article. We introduce a taxonomy based on push-based and pull-based communication, which is useful to categorize both the legacy and the AI-driven access schemes. We provide MAC protocol design guidelines for pull- and push-based communication in terms of goal-oriented criteria, such as timing and data relevance. We articulate a framework for co-existence between pull and push-based communications in 6G systems, combining their advantages. We highlight the design principles and main tradeoffs, as well as the architectural considerations for integrating these designs in Open-Radio Access Network (O-RAN) and 6G systems.

翻译：5G系统中的媒体接入通过网络资源切片技术来适配多样化的业务类型。6G无线系统预计将高度依赖人工智能（AI），从而催生数据驱动和目标导向的通信模式。这拓展了媒体接入控制（MAC）协议的设计空间，也是本文的研究重点。我们提出了一种基于推送式与拉取式通信的分类体系，该体系可用于对传统接入方案与AI驱动的接入方案进行归类。我们针对拉取式和推送式通信，从目标导向准则（如时序和数据关联性）的角度提供了MAC协议设计指南。我们阐述了一种在6G系统中实现推拉通信共存的融合框架，以结合两者的优势。最后，我们重点探讨了设计原则与核心权衡关系，以及在开放无线接入网（O-RAN）和6G系统中集成这些设计时的架构考量。