Telecommunication Base Station

The role of a base station in modern life is comparable to that of water or electricity. The electromagnetic signals it produces surround us continuously, much like the air we breathe, ensuring that communication signals reach everywhere quickly and reliably, linking our phones to the wider world.

Many people assume that the tall steel tower represents the entire base station. In reality, that structure only supports the antennas and is just one part of a much larger system. A complete base station includes both visible structures and many hidden components working together.

A communication base station is generally made up of several key parts:

Antenna and feeder system: handles transmitting and receiving signals, including antennas and feeder cables;
Radio frequency (RF) unit: generates signals and extracts information, playing a crucial role;
Baseband unit (BBU): processes data and acts as the core processing center;
Support systems: provide infrastructure such as towers, equipment rooms, power supply, and cooling systems.

During the 2G and 3G periods, base stations typically had a two-layer architecture.
With the introduction of 4G LTE, this structure was simplified into a single-layer system known as the eNodeB (eNB).

A typical 4G eNodeB includes the following elements:

Antenna and feeder system: how signals are transmitted
Most base stations do not require specially built towers and are often installed on existing rooftops. The vertical panel-like structures commonly seen on rooftops are antennas. In areas with fewer buildings, dedicated towers may be constructed, with multiple rectangular antennas mounted at the top.

Antennas are responsible for both sending and receiving signals. They direct signals from the RF unit toward mobile devices and can focus electromagnetic waves in specific directions, similar to how a flashlight beam follows a target.

They also capture weak signals from phones and pass them back to the RF unit for processing.

Typically, a base station uses three antennas, each covering about 120 degrees, together forming full 360-degree coverage.

If you look beneath the antennas, you will notice black cables running downward. These are feeder cables, which connect the RF unit to the antennas and carry electromagnetic signals, forming the antenna feeder system.

Following these cables leads to a metallic box located near the antenna—this is the RF unit.

The RF unit, often called the Remote Radio Unit (RRU), is responsible for handling radio signals. It converts data into electromagnetic waves for transmission and receives incoming signals from mobile devices. It also filters interference and extracts useful information before sending it to the baseband unit.

Inside the RRU are multiple modules that can support different communication standards such as 2G, 3G, 4G, and even 5G.

Equipment room: ensuring stable operation

The equipment room supports the entire system and requires several essential resources.

Power is the most critical. Electricity from the grid is converted from AC to DC to supply the equipment. Backup batteries are also installed to maintain operation during power outages.

Transmission equipment connects different parts of the network, ensuring data flow.

Because the room is enclosed and equipment generates heat, cooling systems such as air conditioning are necessary to prevent overheating and maintain proper performance.

Baseband unit (BBU)

Inside the equipment room, there is usually a cabinet containing a compact device with many cables and blinking indicator lights—this is the baseband unit.

The BBU processes digital information. It prepares outgoing data for transmission via the RF unit and antennas, and also handles incoming signals from mobile devices after they pass through the RF unit.

In addition to the BBU, cabinets may also contain power and transmission equipment.

These can be identified easily:

Devices with many red, black, and blue cables are typically power systems;
Equipment with numerous fiber ports, network interfaces, and yellow fiber cables is usually related to data transmission.