What is OpenRAN

In order to clarify what OpenRAN is let’s start from RAN. A radio access network is a technology that connects individual devices to other parts of a network through radio connections. It is a major part of modern telecommunications, with LTE and 5G network connections for mobile phones being examples of radio access networks.

From infrastructure perspective we have a split for D-RAN, C-RAN, vRAN and O-RAN 

D-RAN stands for “Distributed RAN”

D-RAN is a classical setup, from which an evolution towards OpenRAN starts. RRU (Remote Radio Unit) and BBU (BaseBand Unit) are co-located at every cell site. They run proprietary applications on specialized hardware. Each radio site with all of its functions are in a single location and connected back to the core network through backhaul.

C-RAN (Also CRAN) stands for Centralized RAN or Cloud RAN. In C-RAN the BBUs from several sites are pooled together and located in one location. This leads to more efficient use of computing resources. Still software and hardware is coming from a single vendor and runs in bare metal setup.

vRAN decouples the software from hardware by virtualizing Network Functions. It uses virtual machines (VNF approach) or containers (CNF approach) to deploy CU and DU on top of COTS servers. 

vRAN and C-RAN are very similar. Only difference is that C-RAN uses proprietary hardware while vRAN deploys on top of COTS servers, the same as you can find in a typical IT datacenter. 

While vRAN is a closed network, as RU, DU and CU, which are all part of the RAN, are provided by a single vendor and use internal means of communication instead of open interfaces.

In OpenRAN, the O-RAN alliance made a great job creating a specification for open fronthaul, mid haul and backhaul interfaces.

This means that finally you can mix and match different vendors, and use different approaches depending on what is the 

The Open RAN architecture as described by O-RAN alliance looks like:

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