In this research report, we consider and analyze use cases related to the notion of dApps, lightweight, programmable, distributed applications that complement the scope of xApps and rApps by performing customizable data-driven tasks in O-RAN Distributed Units (O-DUs) and O-RAN Centralized Units (O-CU-CP and O-CU-UP). We propose 10 exemplary use cases that relate to spectrum management, scheduling, energy efficiency, traffic classification. Based on this analysis, we identify the requirements for the dApps architecture, including flows for data in and out of the O-DUs and O-CU-CP/UP and dApps, and compare real-time control solutions based on (i) standalone dApps or (ii) a real-time RAN Intelligent Controller (RIC) hosted within the RAN. This research report serves as an introduction to further investigation in the area of real-time control and optimization of the next generation of the O-RAN architecture.
