cloud radio access network (C-RAN)

What is a cloud radio access network (C-RAN)?

A cloud radio access network (C-RAN) is a centralized, cloud computing-based architecture for radio access networks. A C-RAN enables large-scale deployment, collaborative radio technology support and real-time virtualization capabilities.

A C-RAN is an evolution of the current wireless communication system and uses the latest common public radio interface standard, coarse or dense wavelength-division multiplexing technology and millimeter wave (mmWave) transmission for long distance signals. The C in C-RAN can stand for centralized or collaborative.

A RAN establishes a connection or communication between base stations and end users. In the C-RAN architecture, baseband units (BBUs) relocate from individual base stations to a centralized control and processing station, often referred to as a BBU hotel.

The BBU hotel connects to the network with high-speed optical fiber and maximizes the distance between cells. This type of cloud computing environment operates on open hardware and network interface cards that dynamically handle fiber links and interconnections within the station.

C-RANs are significant in the future progression of wireless technology, such as 5G and the internet of things. With easier deployment and scaling capability, the transition from Long-Term Evolution to 5G networks will rely heavily on C-RAN development. It also provides a cost-effective, manageable approach to support more users.

Image of C-RAN architecture
C-RAN comprises a mobile switching center, a BBU hotel and a remote radio head.

Components of C-RAN

C-RAN networks comprise three primary components:

  1. A BBU hotel. This is a centralized site that functions as a data or processing center. Individual units can stack together without direct linkage or interconnect to dynamically allocate resources based on network needs. Communication between units has high bandwidth and low latency.
  2. A remote radio unit (RRU) network. Also known as a remote radio head, an RRU is a traditional network that connects wireless devices to access points.
  3. A fronthaul or transport network. Also known as a mobile switching center, a fronthaul or transport network is the connection layer between a BBU and a set of RRUs that use optical fiber, cellular or mmWave communication.

Advantages of C-RAN

Some advantages of C-RAN are the following:

  • enables higher spectrum efficiency;
  • is more cost- and footprint-effective due to less hardware;
  • leads to lower heating, cooling and power requirements;
  • creates a more simplified, scalable and flexible network;
  • supports a larger number of mobile users and wireless standards;
  • enables efficient network upgrades, enhancements, testing, monitoring and maintenance;
  • pools resources or reuses infrastructure;
  • achieves faster speeds than distributed RANs; and
  • uses cloud computing open platforms and real-time virtualization to dynamically allocate shared resources between BBUs.

Editor's note: This article was republished in January 2023 to improve the reader experience.

This was last updated in January 2023

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