RRU (remote RU)

RRU stands for Remote Radio Unit, also known as Remote Radio Head (RRH). It is a key component in modern wireless communication systems, particularly in cellular networks. An RRU is responsible for transmitting and receiving wireless signals between user devices and the base station.

Traditionally, in a cellular network, the base station consists of two main components: the Baseband Unit (BBU) and the Radio Frequency (RF) Unit. The BBU processes the digital data and handles the control functions, while the RF Unit handles the conversion of digital data into analog signals for transmission over the air and vice versa. These two units are physically connected by coaxial cables or fiber optic cables.

However, with the introduction of RRUs, the RF Unit is separated into two parts: the RRU and the Baseband Unit. The RRU is responsible for handling the radio frequency functions, including signal amplification, filtering, modulation, and demodulation, whereas the Baseband Unit takes care of the baseband processing tasks.

The RRU is typically installed at the cell tower or antenna site, closer to the antennas themselves. It is designed to be lightweight, compact, and weatherproof, allowing it to withstand outdoor conditions. By locating the RRU near the antennas, the need for long and expensive coaxial or fiber optic cables is reduced.

The communication between the RRU and the BBU is achieved through a high-capacity digital interface, such as Common Public Radio Interface (CPRI) or Open Base Station Architecture Initiative (OBSAI) protocols. These interfaces enable the transfer of baseband data and control signals between the RRU and BBU.

Some key advantages of using RRUs include:

1. Improved network performance: By locating the RRU closer to the antennas, the signal loss due to long cable runs is minimized, resulting in improved signal quality and coverage.
2. Enhanced flexibility: RRUs allow for easier deployment and expansion of wireless networks. They can be easily added or removed without the need for major changes to the infrastructure.
3. Cost savings: The use of RRUs eliminates the need for extensive coaxial or fiber optic cables, reducing installation and maintenance costs.
4. Energy efficiency: RRUs consume less power compared to traditional RF Units, resulting in energy savings and reduced operating costs.

Overall, RRUs play a crucial role in modern cellular networks by providing a flexible and efficient solution for wireless signal transmission and reception. They help improve network performance, increase coverage, and enable the deployment of advanced wireless technologies.