The UK government recently announced a new set of principles for industry roll of Open RAN solutions at the Open RAN World event in Berlin. But what is Open RAN, why do we need it and why is it something that government is issuing guidance on? Well, let’s first look at how a traditional mobile, cellular network is constructed.
How a mobile, cellular network works
Mobile, cellular networks fundamentally consist of two domains: The Radio Access Network or RAN and the Core Network or Core.
The RAN is the link between the network and the phone or mobile device. There are two parts to the RAN, the antennae that sits atop the radio mast, plus the base station that normally sits at the bottom. The antennae transmits and receives radio signals from a mobile device, it makes the wireless connection with it. While the base station digitises that signal and connects it with the network. These two elements are traditionally co-sited at the radio mast.
The Core provides the management functions to make the network work. The Core manages user authentication for the services they use, enables operators to manage billing, control handover as a mobile device moves from on cell to another and critically connects the mobile device to the internet.
Why do we need Open RAN?
Historically, RAN vendors focussed on adding overall functionality and capability to their products at the expense of interoperability with other vendor’s equipment. The resultant equipment made it difficult to mix radio and baseband products from different vendors and in most cases, they came from the same supplier. The industry then consolidated around the suppliers with the best capabilities, creating an ecosystem of proprietary equipment. Open RAN seeks to change this dynamic, by redefining and standardising the functionality to create a more diverse ecosystem of vendors, it enables operators to mix and match equipment from different suppliers.
What does Open RAN look like?
The Open RAN environment has defined three main units, the Radio Unit (RU), the Distributed Unit (DU) and the Centralised Unit (CU). The RU is either located near or integrated into the antennae and deals with all the radio elements whereas, the DU and CU are the digital parts of the base station and deal with delivery to the network. The DU is located close the RU whereas, the CU can be located near to the Core creating a distributed system. The key tenant of Open RAN is to make the protocols and interfaces between these elements open and standardised, creating interoperability between different manufactures.
Why is the Government interested in this?
Since the concerns first surfaced about Huawei, the 5G network is now regarded as critical national infrastructure that needs to be protected. The UK therefore wants a more diverse supply chain that avoids a few suppliers dominating the ecosystem. It has stated the following in its principles”.
“Increasing vendor diversity for telecommunications networks is an essential goal for the UK and other governments internationally, to safeguard security, resilience, innovation and competition in critical national infrastructure and beyond”.
It also sees the opportunity for the UK to be a leader for Open RAN technologies, creating a £250 million 5G Diversification Strategy that sets out where the government will help new vendors to invest in Open RAN technologies and enter the market.
Open RAN is therefore a key element in removing the dominance of a few suppliers in the 5G ecosystem and will play an increasing role in the development of 5G infrastructure in the UK.