Advantages of RRH | Disadvantages of Remote Radio Head

This page covers advantages and disadvantages of Remote Radio Head (RRH) and its basics. It mentions benefits or advantages of RRH and drawbacks or disadvantages of RRH.

Introduction : Remote Radio Head (RRH) is a technology used in wireless communication systems particularly in cellular mobile networks. It separates radio frequency (RF) functionality and baseband functionality in two separate modules known as RE and REC respectively. The RE module (known as radio front end module) is fixed very close to the RF antennas. REC is installed farther away from the base station cell site and it is connected with core network on the other side. Both RE and REC modules are connected using fiber optic cables. CPRI (Common Public Radio Interface) and eCPRI (Enhanced CPRI) are widely used interface protocols in RRH deployments especially in 4G LTE and 5G networks.

The figure depicts base station with RRH. CPRI carries digitized baseband signals including IQ data, control & management fields and synchronization information over fiber optic cables at high data rates. As shown three fiber optic cables are laid out to carry information from single BBU to three Remore radio units and RF antennas.

Example of one such RRH is Ericsson Radio 2219 that can be installed close to the antenna. It can be located up to 40 Km from baseband unit (BBU). Fiber optic cable is used between single baseband unit and multiple radio units connected in cascade or star configuration. It supports GSM, WCDMA and LTE with up to 8 carriers. It requires -48V DC power supply for its operation. There are other remote radio head (RRH) models available from Ericsson.

Benefits or advantages of RRH

Following are the benefits or advantages of RRH.
➨By locating radio heads closer and using fiber optic cables between BBU and radio end, signal loss is minimized compared to traditional base stations. This results in improved signal quality and better overall network performance.
➨RRH allows easier installation of antennas in various locations which includes hard to reach areas and densely populated urban regions. This flexibility helps to expand coverage and increases network capacity.
➨Radio heads are placed closer to the RF antennas. Hence less power is required to transmit the signals due to low signal loss. This reduces energy consumption and operational costs.
➨Centralized baseband processing allows efficient resource allocation and interference management, This leads to improved network performance and reduction in co-channel interference.
➨RRH technology enables easier upgrades and modifications to the baseband unit (BBU). Moreover change in remote radio heads or antennas are not required. RRH based base stations are scalable and future proofs against technological advancements and changes in network standards.
➨With RRH, single baseband unit can serve multiple remote radio units or antennas. This consolidation of equipments reduces physical footprint of cell sites. Hence it is easier to install and maintain RRH based network infrastructure in congested urban areas.
➨CPRI and eCPRI protocols are vendor agnostic protocols which defines interface between baseband unit (BBU) and remote radio units. Hence BBUs and remote radio units from different manufactures or vendors can be installed at a single cellular site without any interfacing or interoperability issues.
➨The technology used in Remote Radio Head (RRH) development is compatible with various advanced wireless cellular technologies such as 4G LTE, 5G and beyond. This makes it suitable for future network evolutions.

Drawbacks or disadvantages of RRH

Following are the limitations or drawbacks or disadvantages of RRH.
➨RRHs require high speed fiber optic cables between BBU and RRHs. The deployment of fiber infrastructure can be costly, especially in remote or challenging terrains.
➨Remote management solutions are used for maintenance of RRHs but it still requires skilled personnel for on-site troubleshooting and repairs.
➨The distance between BBU and radio units need to be within certain range to maintain optimal signal quality. Longer distances may require signal repeaters or additional equipments.
➨RRHs installed in outdoor environments must withstand various weather conditions such as extreme temperatures, rain and humidity.
➨As the network expands, more RRHs are added. This can lead to increased fiber requirements and potential capacity constaints in the fiber network which requires careful scalability planning.

Conclusion : Overall, RRHs (Remote Radio Heads) play a vital role in WiMAX, 4G LTE, and 5G NR cellular systems. It enables efficient RF processing, improved network coverage and enhanced network performance to meet the growing demands of wireless communication services. Moreover software upgrades to Physical layer-1 as per change in existing standards or during introduction of any new standards have become very easier. Hence new products can be launched quickly.

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