Medium Access for Push-Pull Data Transmission in 6G Wireless Systems

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.

💡 Research Summary

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The paper addresses the emerging need for medium‑access‑control (MAC) mechanisms that can support the AI‑driven, goal‑oriented communication paradigm expected in sixth‑generation (6G) wireless systems. While 5G relied on network slicing to allocate resources for heterogeneous traffic classes, the dynamic nature of AI‑based decision making and the emphasis on the Value of Information (VoI) render static slicing insufficient. To bridge this gap, the authors introduce a taxonomy that classifies existing and future MAC schemes along two orthogonal axes: push‑based versus pull‑based communication, and classical versus AI‑driven (semantic/goal‑oriented) operation.

Push‑based schemes are event‑driven: a device transmits immediately when its locally measured data are deemed informative. This yields low latency for anomaly detection but suffers from random‑access collisions and limited coordination. Pull‑based schemes, in contrast, are centrally orchestrated; the base station (BS) maintains a digital twin (DT) of the environment, predicts which data are likely to be useful, and schedules devices to transmit in reserved slots. Pull‑based access eliminates collisions but can be slow to react to unexpected events because it relies on statistical models rather than actual observations.

To exploit the complementary strengths of both approaches, the authors propose two novel frame structures that enable the coexistence of push and pull traffic within the same system.

1. Contention‑Free Pull / Contention‑Based Push (CFC‑pull/push) – A frame of S slots is divided by a control parameter α∈