Radio Access Network, 5G RAN, vRAN, and Private RAN

- Overview

The radio access network (RAN) is the part of the communication system that traditionally connects devices supporting cellular radio capabilities (e.g. 4G LTE, 5G) back to the public and/or private mobile core network through the existing network backbone. Specifically, cell phones and other devices send and receive radio signals from the RAN network's radio transceivers to connect to the core network.

The RAN has been in use since the beginning of cellular technology and has evolved through the generations of mobile communications (1G through 5G). Components of the RAN include a base station and antennas that cover a given region depending on their capacity. 

Radio access networks provide radio access and coordination management of resources across radio sites. For example, your cell phone wirelessly connects to a core network and the RAN transmits its signal to various wireless endpoints, along with other network traffic. Depending on the type of RAN it is, the network controller handles radio resource management, mobility management and data encryption over a circuit-switched core network or a packet-switched core network.

- Types of Radio Access Networks

There are many different types of radio networks, mainly GRAN, GERAN, UTRAN and E-UTRAN. There are others, such as CRAN, VRAN, and ORAN. 

A single handset/telephone can also be connected to multiple radio access networks simultaneously. Phones with this feature are sometimes called dual-mode phones. For example, cell phones often support both GSM and UMTS (aka "3G") radio access technologies. Such devices seamlessly transfer ongoing calls between different radio access networks without the user noticing any interruption of service.

- The Evolution of the RAN

The RAN has evolved from first generation (1G) to fifth generation (5G) cellular networks. With the development of fourth-generation (4G) technology in the 2000s and the introduction of the Long-Term Evolution (LTE) RAN by the Third Generation Partnership Project, significant changes have taken place in the radio access network and core network. In 4G, system connectivity was based on Internet Protocol (IP) for the first time, replacing previous circuit-based networks.

Now, with LTE Advanced and 5G, there are improvements in the form of centralized RAN, also known as cloud RAN (C-RAN), and multi-antenna arrays, such as multiple-input multiple-output (MIMO).

Since the introduction of the first cellular networks, the capabilities of the RAN have expanded to include voice calls, text messages, and video and audio streaming. The types of user equipment using these networks have increased dramatically, including vehicles of all types, drones, and IoT devices.

- Private RAN

Public Radio Access Networks (RANs) are typically built using proprietary single-vendor infrastructure and then operated by telecom or network operators.

A private RAN is different because it can be operated by an organization but still managed by a network operator. Private RANs provide local connectivity for large venues, factories, industrial operations, or locations outside normal network coverage.

Some places where private RAN is deployed include mining operations, oil and gas operations, large venues and university campuses.