About OpenRAN


Tom explains the basics of OpenRAN and why it’s important to cell phone providers and customers alike.

Featuring Tom Merritt.



A special thanks to all our supporters–without you, none of this would be possible.

Thanks to Kevin MacLeod of Incompetech.com for the theme music.

Thanks to Garrett Weinzierl for the logo!

Thanks to our mods, Kylde, Jack_Shid, KAPT_Kipper, and scottierowland on the subreddit

Send us email to [email protected]

Episode Script
My congressman was saying something something about OpenRAN?
Does it have something to do with 5G?
Or is it related to the whole Huawei US trade thingy?
Are you confused?
Don’t be.
Let’s help you Know a Little more about OpenRAN.

A Radio Access Network or RAN is part of a mobile telecommunication system. It’s the part of the system that connects your device, like your cell phone to the core network. When you see those antennas on buildings or fake palm trees, those– along with the base stations they’re connected to– are the RAN.
Let’s say you want to watch a YouTube video of Korean pop idol, IU. You tap a button on your phone, your phone converts that to a radio signal that is broadcast out and received by the antenna on a RAN base station. The RAN base station digitizes that radio signal and connects it to the CN or core network. The Core Network handles things like authenticating you, switching phone calls, connecting you to the internet and handing your connection over from one RAN to base station to the next as you move. Since you’re trying to watch a video off the internet, the CN in this case sends your request to the Internet where it heads off to YouTube. YouTube finds the IU video you want and sends it back through the Internet to the Core Network which sends it to the right RAN base station to convert it to the mobile network signal and broadcast it back out to your phone, which converts back from a radio signal into a YouTube video of IU singing “Yellow C-A-R-D.”
Different radio access networks were implemented for different network services like GSM and LTE. So when a new network technology comes along– like those in the 5G systems– you’ll need new RAN equipment to run it.
Historically companies buy all their equipment from one company, like Nokia, Ericsson and Huawei. While it’s technically possible to have different vendors for the different parts you need to build a network, the vendors haven’t historical made that easy. Hardware and software are tightly integrated. The interfaces have not interoperated with other vendor’s hardware. So once you buy into one of these equipment makers for your RAN you’re pretty much stuck buying from that vendor from then on. If you want to switch vendors mid-deployment, say because your country decided to block one of the vendors from selling you more equipment, you have to rip out all their RAN equipment and replace it. Which costs money and time.
Unless, you’ve got OpenRAN!
OpenRAN is one of many projects from the non-profit Telecom Infra Project led by Intel, Facebook, Nokia, Deutsche Telecom, Vodafone, Telefonica, and BT Group. OpenRAN aims to enable an open ecosystem of RAN solutions. It works alongside the O-ran alliance founded by AT&T, China Mobile, Deutsche Telekom, NTT DOCOMO and Orange and made up of multiple operators along with software and equipment makers. The O-ran alliance defines the specs for OpenRan implementation.
Open RAN breaks up the RAN system into three building blocks.
The radio Unit or RU handles receiving and transmitting radio signals, amplifying them and digitizing them. It’s usually in or near the antenna.
The Distributed Unit, or DU is close to the radio unit and the centralized unit or CU is close to the core. Both are part of the base station and handle sending the digitized signal into the Core Network and sometimes the two are referred to collectively as the Baseband Unit or BBU.
So going back to our earlier YouTube video example, your YouTube video request is received by the RU, handed to the DU then to the CU where it goes into the network to get the video by IU. Got it?
Anyway let’s get to the why of all of this.
Flexibility! You can buy parts from whoever has them cheapest.
You can use one supplier for radios – the RU– but choose another supplier for the processors in the DU and CU.
A network can use technology from multiple companies, enabling competition and hopefully reducing prices. And even switch to a different vendor mid-deployment without having to rip anything out.
That’s made even easier because of the possibility of 3rd-party testing. Radios that meet the 3GPP industry standard specs and O-Ran specs can be tested independently. An operator doesn’t have to test radios in their own labs because the standard means it will work in any standards compliant network. That makes it easier to buy low-cost radios without having to worry about systems integration and the costs and lock-in that come with it.
The O-ran Alliance has standardized 11 interfaces within the RAN including fronthaul between the RU and DU, Mid-haul between the DU and CU and Backhaul going from the RAN to the Core.
The O-Ran alliance also is developing RIC, the RAN Intelligent Controller to be embedded in the network for operation and optimization to happen without needing a human involved. That’s especially important given heh complexity of 5G networks.
AND OpenRAN lets you run software-based network functions on any standard commercial off-the-shelf server thanks to the open interface. So whatever RAN parts you buy can work with whatever servers run your core network.
Another benefit of OpenRAN is it can be deployed along with vRan which virtualizes network functions like the DU and CU to run on any cloud server close enough to the base station. Multiple network operators can run Virtual Network Functions, or VNF on the same platform reducing infrastructure costs. You don’t have to build new infrastructure for every network operator. They might want to anyway but the option is now there.
Most telcos and chip makers are part of O-Ran as are Nokia, Ericsson and Cisco and many other interested parties. So it has momentum.
A word to the actual network engineers out there. I know this is WAY oversimplified but hopefully this gives the non-industry folks an overview of what OpenRan means.
What does it all mean to you non-industry folks? Well it might mean more networks and hopefully will mean cheaper service. And when you hear politicians or PR people talking about OpenRAN as a solution or impediment to something they want now you’ll know what they’re talking about.
In other words, I hope you know a little more about OpenRAN.