Radio access networks (RANs) are key points in how cellular networks function. For most of RAN’s history, a small selection of vendors has monopolized the RAN market and increased overall cost while decreasing freedom of choice for providers.
Especially as 5G becomes a more concrete reality in both enterprise and public 5G instances all over the globe, a growing segment of 5G infrastructure providers and some RAN vendors are supporting an open RAN movement, which many believe will make 5G more accessible, affordable, and supportive of industry-specific needs. As operators continue to push for open RAN standards and best practices, it becomes increasingly important to understand open RAN and the role it plays in 5G expansion.
What is RAN?
The radio access network (RAN) is one of two primary domains in a mobile cellular network; the other component is the core network. The RAN relies on both antennas and base stations to manage signal and service. While the antenna manages both signal reception and transmission for mobile devices, the signal is then transformed by base stations so that it can be digitally interpreted and connected to the rest of the network.
Traditionally, network operators have only been able to work with one RAN vendor for each component they need, especially since the interoperability of different vendors’ RAN products has never been emphasized. As RAN has changed to meet 5G and other mobile networking needs over time, new types of RAN, such as open RAN and cloudRAN (or vRAN), have become available.
What is Open RAN?
Open RAN is the practice of separating RAN into different components— the radio unit (RU), the distributed unit (DU), and the centralized unit (CU)— and assuring that the interfaces and protocols amongst these three components are open to communicate and work with each other. In opening the RAN with these three areas of interoperability, different vendors can offer products and services for each part of the RAN. This opens up new opportunities for both vendors and operators, as operators can choose whichever vendors they want for each unit.
The idea behind open RAN came to fruition through O-RAN, an operator-led alliance that promotes more open competition and interoperability amongst RAN vendors and their products. The organization has also heavily emphasized shifting RAN infrastructure needs to software rather than traditional hardware, which is a big reason why cloudRAN and open RAN are frequently discussed together.
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Core Features of Open RAN Infrastructure
Open RAN infrastructure relies on and offers key features like a service management and orchestration framework, cloud application development and security support, AI and ML automation, and 3GPP-defined interfaces.
Other core features of Open RAN infrastructure include:
- Radio unit (RU): typically part of the antenna, the RU is where radio frequencies are transmitted and otherwise managed.
- Distributed unit (DU): a computation piece within the base station that is typically close to the RU.
- Centralized unit (CU): a computation piece within the base station that is typically close to the core.
- Fronthaul: interfaces that have been opened up between the RU and DU.
- Midhaul: interfaces that have been opened up between the DU and CU.
- Backhaul: interfaces that have been opened up between the CU and the core.
- RAN intelligent controller (RIC): a controller that can be customized to program and add programmability to other areas of the RAN.
How Open RAN Supports 5G
5G networks offer the ultra-low latency, bandwidth, and speed necessary for new technologies such as the Internet of Things (IoT) and artificial intelligence (AI)-powered smart devices. However, 5G is not nearly as accessible and effective when traditional radio access networks drive up infrastructure costs, decrease overall service quality, and limit operator innovation. Many experts believe open RAN is crucial to wider-spread 5G networks for the following reasons:
Open RAN decreases vendor monopolies and increases competition
Traditional RAN has made it difficult for smaller or lesser-known RAN vendors to reach their target audiences, especially as a lack of RAN interoperability forced customers to rely on big providers who could meet all their needs. Open RAN has started to open up the infrastructure in the network, meaning RAN providers can focus on offering a handful of RAN products, services, and use cases.
The open approach ultimately leads to fewer monopolies, which levels the playing field for providers and forces them to maintain higher standards if they want to hold onto their customers. These higher standards are optimizing RAN to meet current and future 5G networking requirements.
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Open RAN avoids vendor-lockin
Customers also have the freedom to select different providers for different needs and price points, because open RAN components are designed to work in a multi-vendor ecosystem. Cost-savings are important in 5G development because 5G requires more radio towers in closer proximity to users in order to work effectively. Lower costs, driven by open RAN, will likely make it possible for network operators to reach more rural and global audiences with more affordable infrastructure.
The freedom of choice not only has the potential to save operators money on RAN infrastructure, but it also opens up the opportunity for operators to discover new integration and setup possibilities, thus further expanding the potential for 5G-powered innovations.
Open RAN offers specialized industry- and event-based support
Multi-vendor support provides the strengths of each available vendor. This can be particularly valuable for users in a specialized industry who need more support or features in a certain area of the RAN; they can rely on a quality vendor for that piece without being required to use that vendor for all pieces. Open RAN also offers support for predicted network traffic increases.
A great example of open RAN in action on a 5G network is event-based network optimization. If a concert venue, airport, or other large venue wants to improve network services or boost them with AI for a designated time period, the flexibility of several vendors makes it possible to meet event-based needs and provide real-time specialized services during network traffic spikes. With many 5G-powered technologies requiring situational features and service increases, this particular open RAN benefit is driving many operators to the O-RAN movement.
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