Challenges and Lessons Learned During Private 5G Open RAN Deployments

Cellular systems were standardised and got open through different specified interfaces, but one major part of this system, the RAN (Radio Access Network) stayed quite closed and very much proprietary until now. RAN would probably continue being closed and proprietary for an unforeseeable future if it wasn’t down to the mobile operators who want a more diverse ecosystem of vendors and are redefining their requirements for the network architecture.The idea of opening RAN has been around for quite some time, since 2002 or even earlier with the creation of an initiative called OBSAI (Open Base Station Architecture Initiative) and CPRI (Common Public Radio Interface), which at the end did not go very far in terms of openness, but a new initiative mainly driven by the mobile operators through O-RAN Alliance founded in 2018 with the intention to break the vendor lock-in, has attracted a lot of attention among the mobile industry players and has led to a number of trials and testbeds globally. These Open RAN testbeds were built and more are being built with an intention to facilitate a commercially-neutral, collaborative environment for testing interoperability and integration of a multi-vendor open RAN architecture.This paper describes the main challenges and the lessons learned during real deployments of private 5G Open RAN networks done by academia and the industry.