# OAI-CU & OAI-DU

## OpenAirInterface
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OpenAirInterface (OAI) is an **open-source software-defined radio (SDR) platform** that enables researchers, developers, and engineers to design, prototype, and test wireless communication systems. It **provides a complete end-to-end solution for wireless communication systems**, including both the physical layer (PHY) and the higher-layer protocol stack. The **OAI architecture is modular and flexible**, allowing users to customize and extend it for their specific needs.

The OAI project **aims to provide a platform for research and innovation** in the field of wireless communication systems. It is designed to be easy to use, with a simple interface and documentation, allowing users to get up and running quickly. OAI supports a wide range of wireless technologies, including 2G, 3G, 4G, and 5G.
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# CU & OAI-CU
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## What is CU
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A control unit, or CU, is circuitry within a computer’s processor that **directs operations**. It **instructs** the memory, logic unit, and both output and input devices of the computer **on how to respond to the program’s instructions**. CU provides support for the higher layers of the protocol stack such as SDAP, PDCP and RRC.
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## OAI-CU (OpenAirInterface Central Unit)
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OpenAirInterface Control Unit (OAI-CU) is a software component of the OAI architecture that provides control plane functionality in a 5G network. The control plane is responsible for handling signaling messages between the user equipment (UE) and the core network (CN) in a 5G network. The OAI-CU implements the control plane protocols defined by the 3rd Generation Partnership Project (3GPP), including the Session Management, Mobility Management, and Call Control protocols.

The OAI-CU provides a flexible and configurable implementation of the control plane, allowing researchers and developers to experiment with different configurations and protocols. It supports both the Non-Standalone (NSA) and Standalone (SA) modes of 5G, as defined by 3GPP.
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# DU & OAI-DU
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## What is DU
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A Distributed Unit is the main processing unit that's responsible for High Physical, MAC, and RLC Layers/Protocols.
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## OAI-DU
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OpenAirInterface Distributed Unit (OAI-DU) is a software component of the OAI architecture that provides user plane functionality in a 5G network. The user plane is responsible for processing and forwarding data packets between the UE and the CN in a 5G network. The OAI-DU implements the user plane protocols defined by 3GPP, including the Radio Resource Control (RRC), Packet Data Convergence Protocol (PDCP), and Radio Link Control (RLC) protocols.

The OAI-DU is designed to be highly scalable and efficient, supporting high data rates and low latency. It is typically implemented on a distributed set of compute resources, such as general-purpose processors (GPPs) or graphics processing units (GPUs). The OAI-DU can be configured to support different network configurations and protocols, allowing researchers and developers to experiment with different network architectures and technologies.
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