Open RAN (O RAN), or Open Radio Access Network architecture is based on 3GPP standards for Radio Access Networks (RAN) but contains many extensions, disaggregates RAN components and makes their interfaces open, aiming to improve flexibility and interoperability. RAN hardware and software are cloudified/virtualized, and it includes intelligent management (SMO). [1]
Those open interfaces aim for mixing components from different vendors and quicker deployment of new services. [1] O RAN standardization is lead by the O-RAN Alliance. [2]
Cloudification means disaggregating hardware and software, making RAN software cloud-native functions running on a general-purpose hardware. [1]
Intelligent open management includes automated management and orchestration systems which can utilize Artificial Intelligence and Machine Learning for life cycle management of network functions. [1]
Open interfaces: standardized open interfaces, such as the O-RAN Alliance's specifications and 3GPP-defined interfaces, facilitate interoperability between disaggregated RAN components. [1]
In Open RAN, the RAN is split into three main blocks: the Radio Unit (RU), the Distributed Unit (DU), and the Centralised Unit (CU). [3]
RAN Intelligent Controller (RIC) is an optional virtualized optimization technology for 5G. It adds programmability to a new or existing RAN and allows SON-like (Self-Optimizing Networks) capabilities. The optimization in RIC is boosted by policy-driven closed loop automation and AI/ML. [4]
The fronthaul interface lies between radio Units (RU) and baseband units (Distributed Units (DU)). It is a focus area in Open RAN. [4]
O-RAN has specified an eCPRI-based 7.2x open interface to be used in the fronthaul, allowing connections between radio units and baseband units of different vendors. [4]
O-RAN Alliance (O-RAN) was founded in 2018 by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO and Orange to promote open mobile networks. [5] [1] O-RAN has over 30 operator members and almost 300 contributors. [1]
O-RAN specifications define the parts of the O-RAN Architecture, which can be used to develop Open RAN solutions. [6]
O-RAN Alliance also handles the activities of the earlier xRAN and C-RAN forums. [4]