FTTA and 5G: Transforming the Way Wireless Networks Are Connected

Compared to traditional mobile networks, 5G networks require higher bandwidth, lower latency, and denser base station deployments. Therefore, the connections within base stations, as well as between antennas, RRUs/RRHs, and BBUs, are becoming increasingly crucial to overall network performance.

What Is Fiber to the Antenna (FTTA)?

Fiber to the Antenna (FTTA) is a network architecture widely used in modern wireless communication systems. It uses fiber optic cables to provide high-speed data transmission between the baseband equipment and radio equipment installed near the antenna.

In a typical FTTA deployment, the BBU, RRU/RRH, antenna, fiber optic cable, CPRI/eCPRI, and fronthaul work together to complete the communication link from the baseband processing unit to the antenna. Next, we present an explanation of the terminology for key components.

BBU(Baseband Unit)

The Baseband Unit (BBU) is responsible for processing baseband signals in mobile communication networks. In traditional base station configurations, the BBU is typically installed in an equipment room or cabinet, while the radio equipment is installed near the antenna. In short, the BBU can be considered the "processing center" of the base station.

RRU(Remote Radio Unit)/RRH(Remote Radio Header)

Remote Radio Units (RRUs) and Remote Radio Headers (RRHs) are radio units installed close to the antenna. Their primary function is to convert and process signals between the digital baseband side and the radio frequency (RF) side. Because they are close to the antenna, they help reduce losses caused by long-distance RF cable transmission. In short, the RRU/RRH acts as a radio interface between the baseband equipment and the antenna.

Antenna

An antenna is a component used to transmit and receive radio signals. It converts electrical signals into electromagnetic waves and transmits them to mobile devices. Therefore, the antenna is the component in a base station that directly interacts with the wireless environment.

Fiber Optic Cables

Fiber optic cables use optical fibers to transmit data in the form of optical signals rather than electrical signals. In FTTA deployments, fiber optic cables are typically used to connect BBUs and RRUs/RRHs, providing high-bandwidth and low-loss data transmission.

Compared to long-distance copper cable transmission links, fiber optic cables offer the following advantages:

• High bandwidth
• Low transmission loss
• Long-distance transmission
• Electromagnetic interference resistance
• Smaller size and lighter weight

For outdoor base station deployments, FTTA fiber optic cables can also be designed with features such as waterproofing, UV resistance, mechanical protection, and ruggedized connectors to withstand harsh environmental conditions.

CPRI / eCPRI

CPRI (Common Public Radio Interface) is a communication interface originally developed to connect baseband equipment and remote radio equipment.

In traditional LTE and early 5G network architectures, CPRI was typically used for fronthaul connections from the BBU to the RRU.

eCPRI (Enhanced Common Public Radio Interface) is a newer interface designed to improve transmission efficiency and better support the needs of modern 5G networks.

How FTTA Works？

If the above technical terms are difficult to understand, you can use a very simple way to understand them:

The BBU is responsible for "processing data," the RRU/RRH is responsible for "processing wireless signals," the antenna is responsible for "transmitting and receiving wireless signals," and the optical fiber is responsible for "high-speed data transmission."