Open RAN
Also known as: O-RAN, open radio access network, OpenRAN
Open RAN, or open radio access network, is an approach to building mobile networks where the equipment and software at cell sites follow open, standard interfaces, so carriers can combine parts from different vendors.
Traditionally, a carrier bought radios, hardware, and software as one package from a single supplier such as Ericsson, Nokia, or Huawei. While Open RAN promises more competition and flexibility, integrating parts from multiple vendors has proven harder and slower than early supporters hoped.
Open RAN, explained at three levels
At home
Think of a desktop PC. You can buy a graphics card from one brand and memory from another because they all plug into standard slots. Traditional cell towers were more like a sealed games console, where every part came from one company. Open RAN defines standard 'slots' between the radio, the computers that process the signal, and the control software, so a carrier can mix parts from different suppliers.
At work
Open RAN is an approach to building the radio access network, the cell sites that connect phones to a carrier, using open, published interfaces between components. That lets carriers buy radios, processing hardware, and software from different vendors and run much of it on ordinary servers. For the industry, the appeal is supplier choice, potentially lower costs, and less dependence on one equipment maker.
At home
A cell site does three jobs. The radio turns signals in the air into digital data. A baseband processor handles the fast, timing-critical work, such as error correction and deciding which phone transmits when. Higher-level software manages connections and handovers between towers. In a traditional site, one vendor's boxes do all three and talk in private formats. Open RAN publishes those formats, so each job can come from a different company and run on standard hardware.
At work
The O-RAN Alliance splits the base station into a radio unit (RU), a distributed unit (DU) for real-time processing, and a centralized unit (CU) for higher-layer functions, connected by the open fronthaul interface known as split 7.2x. It adds a RAN Intelligent Controller (RIC), where third-party apps called xApps and rApps tune traffic, power, and interference. DUs and CUs can run as cloud-native software on commercial servers, often with accelerator cards.
At home
While open interfaces sound simple, the hardest part of a mobile network is the timing-critical processing, which traditionally ran on custom chips tuned for efficiency. Moving it to general-purpose servers can use more power, and getting radios and software from different vendors to work at full performance takes long testing. In my view, Open RAN's real win for ordinary phone users is indirect: it has pushed incumbent vendors to open up, which should mean more competition over time.
At work
Open RAN's main problems are integration, accountability, and performance. With three or four vendors at one site, someone has to test, certify, and own failures, a role carriers or systems integrators must fill. More open interfaces also mean more attack surface, an issue covered by O-RAN Alliance security work and government guidance from agencies such as CISA. Many large deployments, such as AT&T's with Ericsson, are single-vendor Open RAN: compliant interfaces, but one main supplier in practice.
Real-world examples
At home
Fatima read that Canada banned Huawei 5G equipment and wondered how carriers would replace it. She learned Open RAN was one approach meant to give carriers more supplier options.
At work
Carlos is a network planning engineer at a regional Canadian carrier. He's evaluating Open RAN for rural sites, where mixing vendors could cut costs, but he's budgeting extra time for integration testing.
How it compares
| feature | Open RAN | Traditional RAN |
|---|---|---|
| Vendors | Mix and match | Usually one per area |
| Interfaces | Open standards | Proprietary |
| Hardware | Often standard servers | Purpose-built |
| Integration effort | Higher | Lower |
Open RAN trades integration work for vendor choice.
For analysts
For carriers or large private networks, I'd treat Open RAN as a long-term supplier-diversity strategy, with careful pilots, rather than a quick cost saving.
History & origin
The radio access network, the cell towers and equipment that connect phones, was long dominated by a few vendors with proprietary systems. The O-RAN Alliance formed in 2018, led by carriers including AT&T, China Mobile, Deutsche Telekom, NTT Docomo, and Orange, to develop open interfaces. Japan's Rakuten Mobile launched a cloud-native, Open RAN-based network in 2020. Security concerns about Huawei pushed governments to support vendor diversity; Canada announced in May 2022 that it would ban Huawei and ZTE equipment from 5G networks. In December 2023, AT&T signed a roughly US$14 billion deal with Ericsson to move much of its traffic onto Open RAN-compliant equipment, showing that large incumbents could also adopt the model. In my view, Open RAN's biggest effect so far has been pushing traditional vendors to open up, more than creating new winners.