RRH (Remote radio head)
Remote Radio Head (RRH) is a key component in modern wireless communication networks, particularly in the context of mobile networks such as 4G LTE and 5G. It is a part of the base station architecture, which is responsible for transmitting and receiving radio signals between the mobile devices and the core network.
Here's a detailed explanation of RRH, its purpose, and its functionality:
Purpose:
The primary purpose of a Remote Radio Head (RRH) is to enable the separation of the radio frequency (RF) processing from the baseband processing in a base station. Traditionally, base stations were designed as monolithic units where both the RF and baseband processing were integrated into a single unit. However, with the evolution of wireless networks, the RRH concept emerged to address the challenges posed by increasing capacity demands, better coverage, and network optimization.
Functionality:
The RRH performs the following functions within the base station architecture:
a. Radio Frequency (RF) Processing: The RRH is responsible for transmitting and receiving RF signals to and from the mobile devices. It contains RF components, such as power amplifiers, filters, mixers, and antennas, which are used to process the RF signals.
b. Digital-to-Analog (D/A) Conversion: The baseband processing unit generates digital signals that need to be converted into analog signals for transmission over the air. The RRH performs the digital-to-analog conversion, converting the baseband signals into RF signals that can be transmitted wirelessly.
c. Analog-to-Digital (A/D) Conversion: Similarly, for receiving signals from mobile devices, the RRH performs analog-to-digital conversion. It converts the received RF signals into digital signals that can be processed by the baseband unit.
d. Amplification: The RRH amplifies the RF signals to ensure sufficient power for transmission. Power amplifiers within the RRH boost the signal strength before it is transmitted over the air, enabling effective communication with mobile devices.
e. Antenna Interface: The RRH is connected to the antenna, which is responsible for transmitting and receiving the RF signals. It interfaces with the antenna, allowing the signals to be radiated or received from the air.
f. Baseband Unit (BBU) Interface: The RRH is connected to the Baseband Unit (BBU) through a high-speed fiber optic link. The BBU is responsible for processing the digital signals and managing the overall network. The RRH receives baseband signals from the BBU, performs RF processing, and transmits the RF signals to the antenna. Similarly, it receives RF signals from the antenna, processes them, and sends the digitized signals back to the BBU for further processing.
Advantages of RRH:
Remote Radio Head offers several advantages in wireless network deployments:
a. Distributed Architecture: RRH enables a distributed architecture where the RF processing can be located closer to the antenna, reducing signal losses and improving overall system performance.
b. Enhanced Capacity: By separating the RF and baseband processing, RRH enables better capacity scaling. It allows for the deployment of multiple RRHs, each serving a different sector, and sharing the resources from a centralized BBU pool. This enhances the system capacity and improves network performance.
c. Improved Coverage and Flexibility: RRH enables the deployment of small cells and distributed antenna systems, which can be strategically placed to improve coverage in challenging areas. It also allows for the deployment of heterogeneous networks, combining different radio technologies for optimal coverage and capacity.
d. Energy Efficiency: By distributing the RF processing closer to the antenna, RRH reduces power consumption by minimizing the losses associated with long RF cables.
e. Network Optimization: RRH facilitates network optimization and management. It enables dynamic resource allocation, allowing operators to allocate resources to areas with higher demand. It also simplifies network maintenance and upgrades, as RRHs can be easily added or replaced without affecting the overall network.
Overall, Remote Radio Head (RRH) plays a crucial role in modern wireless communication networks by separating the RF processing from the baseband processing. It enables better coverage, enhanced capacity, and improved network optimization, contributing to the efficient operation of mobile networks.