Ericsson RRU Explained: Components, Cables ans Installation
Are you familiar with the component makeup of Ericsson telecom base stations? Do you know the function of an RRU? Today, I will introduce the Remote Radio Unit (RRU)—a key piece of hardware in modern cellular networks (4G LTE/5G)—by covering three main aspects: core hardware composition, cabling and connections, and installation and structure.
Core Hardware Components
Remote Radio Unit (RRU) Body: The main white weatherproof enclosure. It contains the Power Amplifier, Transceivers, and Digital Signal Processing (DSP) units.
Heat Sink: The "fins" on the side of the unit are designed for passive cooling, dissipating heat generated by the high-power electronics inside.
Product Labeling: Contains the model number (e.g., RRUS series), regulatory compliance symbols, and frequency specifications.
Band/Sector Identifier: The yellow/green sticker indicates the specific frequency bands being used (e.g., 1800 MHz and 2100 MHz) and the sector of the cell site (e.g., Sec 1).
Cabling and Connectivity
The cables at the bottom are the "lifeline" of the unit:
DC Power Cable: Usually the thicker black cable. It provides the necessary electrical power (typically -48V DC) to run the unit.
Fiber Optic Links (CPRI):
The cables with yellow markers. These carry high-speed digital data between the RRU and the Baseband Unit (#BBU) located on the ground.
RF Cable (Jumpers)
These connect the RRU to the physical antenna. They transmit the high-frequency radio waves that eventually reach your mobile phone.
RET (Remote Electrical Tilt) Cable:
Sometimes present to allow engineers to adjust the angle of the antenna beam remotely via software.
Mounting and Structural Elements
Mounting Bracket: The heavy-duty metal assembly behind the RRU that secures it to the pole or wall.
Mechanical Tilt Mechanism: Allows for manual adjustment of the unit's vertical angle during installation.
Protective Chassis/Vented Housing: The grey slotted structure next to the RRU, which often houses cable management systems or additional filtering equipment.
In Summary
The RRU acts as the interface between the digital core of the network and the wireless air interface. It takes digital data via Fiber Optics, converts it to Analog Radio Frequency (RF), amplifies it, and sends it to the Antenna to provide cellular coverage to users in the area.