RAN types to remember

A radio access network (RAN) is a major component of a wireless telecommunications system that connects individual devices to other parts of a network through a radio link. The RAN links user equipment, such as a cell phone, computer or any remotely controlled machine, over a fiber or wireless backhaul connection. That link goes to the core network, which manages subscriber information, location and more.

Since the first cellular networks were introduced, the capabilities of RAN have expanded to include voice calls, text messaging, and video and audio streaming. The types of user equipment using these networks have drastically increased, including all types of vehicles, drones and internet of things devices. RAN components include base stations and antennas that cover a specific region, depending on their capacity.

A RAN provides access to and coordinates the management of resources across the radio sites. A handset or other device is wirelessly connected to the backbone, or core network, and the RAN sends its signal to various wireless endpoints so it can travel with traffic from other networks. A single handset or phone could be connected at the same time to multiple RANs, sometimes called dual-mode handsets.

Today, RAN architecture divides the user plane and the control plane into separate elements. The RAN controller can exchange one set of user data messages through a software-defined networking switch and a second set through a control-based interface. This separation enables the RAN to be more flexible, accommodating the network functions virtualization techniques, such as network slicing and high MIMO, that are necessary for 5G.

Open RAN involves developing interoperable open hardware, software and interfaces for cellular wireless networks that use white box servers and other standard equipment, rather than the custom-made hardware typically used in base stations. It has considerable potential to support future edge compute-enabled use cases by distributing, virtualising and disaggregating RAN functionality: providing more choice and flexibility on the RAN components that can be deployed to support service innovation.

A virtual radio access network (vRAN) is a type of RAN with its networking functions separated from the hardware it runs on. The control and data planes of the vRAN are also separated as part of the virtualization. Virtualized RAN, or vRAN, refers to the ability to combine multiple 5G New Radio elements via software with a common core to more cost effectively support higher user capacity.

Virtualizing the RAN makes it more agile and flexible than a hardware-based RAN. A vRAN is more agile in the sense that it is able to adapt to changes in the network faster. This includes ensuring intelligent load balancing and allocating resources based on demand. It also allows change without having to replace hardware throughout the entire infrastructure — all it needs is to update its software.

For many operators, vRAN will serve as a steppingstone in the near term. Analyst predictions even signal that single-vendor vRAN solutions will prevail: 80% of the projected US$11b budget for open RAN is expected to go to traditional incumbent vendors who will offer pre-integrated, proprietary vRAN solutions that contain some internal open interfaces.

C-RAN usually refers to either cloud RAN, a scenario where an operator doesn’t own the infrastructure, or centralized RAN, where an operator needs to minimize the overall footprint of a deployment based on the lack or cost of physical real estate. C-RAN separates the radio elements in a base station into remote radio heads (RRHs). These can be used atop the cell towers for the most efficient radio coverage. RRHs must be connected to centralized baseband controllers via fiber or microwave radio links. Most baseband processing uses standard white box servers.

Upgrading the RAN software can improve the network’s connectivity, efficiency, or security among other functions. With a vRAN infrastructure, network operators can better keep up with security than network operators still using a non-virtualized RAN because bugs and other security issues can be fixed by updating software instead of having to replace hardware on a large scale. A secure network attracts more customers because the more trust the customer base has in a product like a network, the more likely they are to use it.

RAN virtualization is required for 5G networks because the new generation demands more visibility, automation, and adaptability that hardware-based RANs cannot provide. The ability to scale and intelligently adjust the network to changing conditions is significant when the demands on 5G networks increase both from mobile phone users and, more significantly, Internet of Things (IoT) devices. The number of IoT devices is growing. And because many of the devices are interconnected with each other and with the larger network, data is being generated and transmitted at immense volumes.

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