Open RAN is a way of building cellular networks using interchangeable parts from multiple vendors instead of relying on a single equipment maker for everything. In traditional networks, one company (typically Ericsson, Nokia, or Huawei) supplies the entire radio access network as a tightly bundled package, with proprietary interfaces that lock the operator into that vendor’s ecosystem. Open RAN replaces those proprietary connections with standardized, open interfaces so that a radio unit from one company can work with baseband software from another and network intelligence from a third.
The global Open RAN market was valued at roughly $3.18 billion in 2025 and is projected to reach $46.33 billion by 2035, growing at about 31% per year. That trajectory reflects growing interest from mobile operators who want more flexibility, lower costs, and less dependence on a handful of dominant suppliers.
How the Architecture Works
A traditional cell site has two main pieces of hardware: a radio unit mounted on the tower and a baseband unit at its base. These two components communicate through a proprietary link defined by whoever manufactured them. Open RAN breaks this model apart into three distinct, standardized components.
The O-RU (Open Radio Unit) sits at the top of the tower and handles the raw radio signal processing, converting data into radio waves and vice versa. The O-DU (Open Distributed Unit) handles the heavy, time-sensitive computations like channel estimation, scheduling which users transmit when, and calculating signal weights. The O-CU (Open Central Unit) manages higher-level functions like routing data traffic and coordinating resources across multiple cell sites. It can be located farther from the tower, often in a regional data center.
The O-RAN Alliance, the primary industry body defining these standards, specifies exactly where the processing splits between components. Between the radio unit and the distributed unit, it uses what’s called a 7.2x split, which divides responsibilities at the point where data is converted between the frequency domain and the time domain. Between the distributed unit and the central unit, it uses a “split 2” interface that separates user data traffic from control signaling. This separation lets operators scale each piece independently. If user traffic spikes, you can add central unit capacity without touching the radios.
Open RAN vs. Virtualized RAN
These two terms overlap but aren’t the same thing. Virtualized RAN (vRAN) takes the baseband unit’s software and runs it on generic, off-the-shelf server hardware instead of custom-built equipment. This is useful because it means you’re not locked into one manufacturer’s proprietary hardware, but the software interfaces between components can still be proprietary.
Open RAN goes a step further by also standardizing the interfaces between components so that equipment from different vendors can connect and communicate. In practice, a full Open RAN deployment typically combines both concepts: virtualized software running on commercial servers, connected through open, standardized interfaces. You can have vRAN without Open RAN (proprietary software on generic hardware), but most Open RAN deployments are also virtualized.
The RAN Intelligent Controller
One of Open RAN’s most distinctive features is the RAN Intelligent Controller, or RIC. This is a software platform that sits above the radio network and uses data analytics and machine learning to optimize performance in ways that traditional networks handle through static configuration.
The RIC comes in two flavors. The near-real-time RIC runs small applications called xApps that make decisions within about a second, like adjusting which users connect to which cell or managing interference between neighboring sites. The non-real-time RIC runs applications called rApps that analyze longer-term trends and set broader network policies, such as energy-saving schedules or traffic-routing strategies. Both layers accept third-party applications, which means operators or independent developers can build custom optimization tools rather than relying solely on the network vendor’s software.
Real-World Deployments
The most cited large-scale Open RAN deployment is Rakuten Mobile in Japan, which launched as a greenfield carrier built entirely on open, virtualized architecture. The company deployed more than 350,000 macro and small cells using radios from seven different vendors. According to Rakuten’s own reporting, the approach cut capital costs by 40% compared to traditional RAN equipment, and ongoing operating costs run about 30% lower. Extensive automation allowed the network to be built at a pace of 200 sites per day.
Rakuten had the advantage of starting from scratch. Retrofitting Open RAN into an existing network is considerably harder, since operators must integrate new open components alongside legacy equipment that was never designed to interoperate with other vendors’ gear. Still, major carriers including Deutsche Telekom, Vodafone, and AT&T have all run Open RAN trials or partial deployments, particularly for rural coverage and new 5G builds where the cost savings are most compelling.
Interoperability Challenges
The promise of mixing and matching vendors sounds straightforward, but the reality is messier. Testing conducted through the U.S. National Telecommunications and Information Administration’s 5G Challenge program found that simply complying with the same 3GPP and O-RAN Alliance specifications does not guarantee that components will actually work together. Vendors often implement different release versions of the standards, interpret specific requirements differently, or include optional features that other components don’t support.
During interoperability testing, participants spent significant time capturing and reviewing log files, resolving configuration mismatches, and optimizing parameters for each specific combination of equipment. Achieving target throughput under different radio conditions required close collaboration between the host lab, the test equipment vendor, and the contestant, and the optimal settings were different for every team. Barriers to smoother cooperation included lack of dedicated funding to fix software discrepancies, insufficient support in third-party contracts, and subsystems that had been designed for a specific customer rather than for broad interoperability.
These findings don’t mean Open RAN is impractical. They do mean that “plug and play” remains an aspiration rather than today’s reality. Integration still requires skilled engineering effort, and operators should expect a hands-on process when combining components from different suppliers.
Security Considerations
Opening up interfaces between network components creates a wider attack surface than a sealed, single-vendor system. A 2022 assessment by CISA, the U.S. cybersecurity agency, outlined the key risks. The open fronthaul link between the radio unit and the distributed unit is a particular concern: if an unauthorized device gains access to that connection, it could launch denial-of-service attacks against the radio network.
Mitigations include network access controls, physical security hardening of radio units, and certificate-based authentication using mutual TLS (a protocol where both ends of a connection verify each other’s identity). The O-RAN Alliance’s specifications allow operators to choose between this stronger certificate-based approach and simpler password-based authentication, but CISA flagged password-only authentication as weak and vulnerable to brute-force attacks.
The third-party applications running on the RAN Intelligent Controller also need protection. Both rApps and xApps communicate over defined interfaces that require mutual authentication, plus encryption to prevent eavesdropping or message tampering. Because these applications can influence real-time network behavior, a compromised app could degrade service or redirect traffic. Operators need to vet and sandbox these applications much like an enterprise IT department manages software on its servers.
Why It Matters for Carriers and Consumers
For mobile operators, the core appeal is escaping vendor lock-in. When a single vendor controls the entire RAN stack, switching costs are enormous, negotiating leverage is limited, and innovation happens on the vendor’s timeline. Open RAN lets operators choose best-in-class components for each layer, negotiate more aggressively on price, and adopt new capabilities from smaller, specialized companies that couldn’t previously break into the market.
For consumers, the effects are indirect but meaningful. Lower infrastructure costs can translate to broader coverage in areas that were previously too expensive to serve. The RAN Intelligent Controller’s optimization capabilities can improve network performance during peak usage. And a more competitive supplier ecosystem tends to accelerate innovation: when dozens of companies can build components for a network instead of three, new features and efficiency gains arrive faster.
Geopolitics also plays a role. Governments in the U.S., Europe, and parts of Asia have promoted Open RAN as a way to diversify supply chains away from heavy reliance on a small number of vendors, particularly Huawei. Public funding programs in several countries specifically support Open RAN research, testing, and deployment as part of broader telecommunications security strategies.