In recent months, the telecommunications industry has been abuzz with news about various initiatives related to Open RAN. Essentially, Open RAN refers to open and interoperable interfaces within and between the various subcomponents of the RAN: the radio, hardware, or baseband unit and software. From a historical perspective, the evolution of Open RAN for mobile networks closely parallels the transformation of legacy IT networks. This fundamental change was prompted by initiatives like software defined networks (SDN), network function virtualization (NFV) and open source software such as Linux.
Open ecosystem: A catalyst for change
Similar to the extensive and diverse IT ecosystem, Open RAN is supported by a dynamic community of operators, vendors and organizations working to create an open, interoperable and intelligent RAN. This collaboration enables an expansive ecosystem of renewed innovation, supply chain diversity and cost efficiencies. With an open ecosystem that actively encourages new vendors, we are already seeing a noticeable increase in the number of innovative technologies and products in the marketplace.
The positive impact the Open RAN ecosystem is having on the telecommunications industry cannot be overstated. Historically, compatible RAN equipment was only procured from a single vendor. However, this became a noticeable commercial limitation with 4G when radio systems transitioned into two separate hardware subsystems, digital and RF, with a proprietary interface between them. In simple terms, this meant mobile operators did not have the option of mixing and matching RAN equipment between vendors. With the advent of 5G, the digital radio is further dis-aggregated. Without adoption of a non-propriety interface, the RAN must be provided by a single vendor.
Open RAN and 5G
While Open RAN is not limited to 5G, it is especially relevant to it. This is because the rollout of 5G introduces new network architectures and fresh revenue generating opportunities. These include low latency services to enterprises and consumers via public or private networks, fixed wireless broadband and ubiquitous connection of machines, sensors and infrastructure. At the same time, the cost of migrating existing LTE networks to 5G provides an incentive for new approaches.
However, 5G rollouts can be challenging for mobile operators if all RAN equipment must be purchased from a single vendor. Fortunately, true interoperability between various components will help increase vendor diversity, reduce dependence on a single supplier and enhance the security of these networks. Put succinctly, Open RAN has the potential to accelerate the availability of 5G throughout the United States across various deployment models and strategies. This includes expediting small cell deployments—both outdoors and indoors—and broadening the use cases they serve, as well as 5G deployment at the macro and metro layers.
Open RAN and indoor connectivity
Let’s take a closer look at how Open RAN can improve indoor connectivity. According to Mobile Experts chief analyst Joe Madden, Open RAN virtualized solutions offer the industry an “exciting opportunity” for in-building wireless suppliers to potentially create combined coverage and capacity solutions that can scale across different market segments. Specifically, neutral hosts are expected to create new indoor solutions that can evolve from LTE to 5G and provide scalable capacity and coverage solutions for the enterprise market.
From our perspective, Open RAN is clearly a robust enabler of in-building wireless-optimized solutions. This is because small cell vendors often specialize in RAN use cases that have not been the focus of mainstream infrastructure vendors, notably cellular systems for enterprise buildings and large venues. In other words, Open RAN will enable vendors to optimize RAN systems for in-building use without having to adopt a proprietary approach.
An example of this is an indoor small cell solution that leverages open interfaces and virtualization to deliver in-building wireless services by supporting virtualized 5G NR baseband functions. This enables baseband functions to run on x86-based server platforms anywhere in the network to support 5G network slicing – virtual end-to-end networks customized for each application requirement. More specifically, capacity-related control plane functions can be centralized for efficient pooling, while data and media delivery user plane functions can be pushed to the edge for low latency.
As well, indoor small cell solutions can include an O-RAN fronthaul interface to support fronthaul over Ethernet. These are critical to meeting the requirements of enhanced mobile broadband and ultra-reliable low latency communication 5G use cases. Not to be confused with Open RAN, O-RAN drives new standardization of a 3GPP-based open AI/ML enabled RAN architecture with interoperable interfaces, open source software and hardware reference designs.
In addition, indoor small solutions can include support of Open Network Automation Platform (ONAP) framework. ONAP simplifies network on-boarding, provisioning, orchestration and management for operators by providing a common framework across all network elements and services. For 5G Service Management, the O1 Interface specified by the O-RAN Alliance can be leveraged.
Conclusion
Open RAN promotes a sustainable, innovative and continuously evolving multivendor RAN ecosystem. By intelligently disaggregating the RAN, Open RAN enables vendors to optimize specific parts of their solutions for specific use cases. This dynamic ecosystem encourages the adoption of next-generation applications and services that enable new businesses models and revenue streams. Perhaps most importantly, Open RAN can potentially accelerate the availability of 5G throughout the United States across various deployment models and strategies. This includes expediting small cell deployments—both outdoors and indoors—and broadening the use cases they serve, as well as 5G deployment at the macro and metro layers.
Major industry stakeholders continue to make significant strides towards Open RAN solutions for 5G and next-generation wireless networks. However, R&D, standardization and implementation are still ongoing. As part of this dynamic process, we believe it is important for the industry to continue to proactively support the standards and interfaces that operators require for their networks and Open RAN clearly includes multiple examples of this.
