Latin America. Mobile operators are preparing to support Gigabit LTE and 5G technologies; to do this they must make their networks much denser to offer high performance and low latency services. Densification involves the deployment of small cells separated by a short distance from each other over the radio access network (RAN), a landscape where C-RAN (a RAN-enabling architecture for both small cells and macro sites) lays the foundation for 5G technology, and is today a major trend in the wireless industry.
C-RAN can represent a "cloud" or "centralized" RAN, the latter being what operators are doing now. In a traditional macro cellular network, radio units are mounted on top of the tower with antennas, with the fiber typically connected to a baseband unit (BBU) located at the base of the tower. The BBU is the one that processes all the information per hour and links the end user with the central network, in this way each cell site has its own BBU located on site in a certain type of booth or enclosure.
"The C-RAN (centralized) itself can serve a large number of cell sites and replaces the traditional BBUs located on each site. C-RAN technology offers a better organized and more efficient alternative, as it allows to extract the BBUs from each site and centralizes them. The total amount of BBU equipment required is reduced and the centralized RAN opens the way for the eventual major shift to the Cloud RAN, where the processing of the BBU has been virtualized. This version of C-RAN is expected to be a critical enabler for 5G, but before virtualization comes centralization, and that's where the wireless industry is now," said Wes Oxlee, Director of Business Development at CommScope Connectivity Solutions.
The future is fiber
Centralizing BBUs in a C-RAN hub, a new layer in the network known as fronthaul is introduced. This layer is the link between the BBU group and the remote radio units at the cell site or at the location of the small cells. Fiber is the best option for this, since it offers greater bandwidth, however, due to the cost of placing a new network, in addition to maximizing existing resources, some network operators are using their existing fiber assets, such as the FTTH (fiber-to-the-home) network, through a technique called fiber network convergence.
"Fiber network convergence refers to the combination of multiple services within a single access network. In other words, a single medium is used to deliver all or multiple forms of communication services," Oxlee added. "The process of fiber optic network convergence is primarily driven by the development of enabling technologies, user demand, and the capabilities of service providers."
FTTH networks have an extensive footprint that is perfect for supporting fast-growing mobile applications such as distributed antenna system (DAS), small cell backhaul, and Wi-Fi. In addition, regional operators and providers that historically started their networks using Wi-Fi radios to serve their users, today are also rapidly migrating to FTTH as a means to increase their competitiveness and provide differentiated services.
In this regard, Eduardo Jedruch, President of the Fiber Broadband Association LATAM Chapter, pointed out: "with all this market movement, in Latin America there are impressive growth rates in new FTTH facilities for the coming years, numbers that are able to match mature markets such as North America and Europe. By the end of last year there were just over 4.5 million homes connected, a growth of 25% compared to 2015; and with about 23 million homes passed, 18% more than in 2015. These numbers show that fiber is taking a big place in the Latin American market, which implies a positive development and adoption throughout the region."
C-RAN, the first step to 5G
In addition to lower capital expenditure, lower maintenance costs and better use of space, the C-RAN offers many advantages. Operators can often leverage existing plant or cell site infrastructure to create centralized C-RAN, implying that while saving on hardware costs, this model can generate significant savings in terms of power, cooling, and site leasing costs.
"The first step on the road to 5G is the centralization of the RAN. Operators are doing this today by creating centralized BBU clusters and leveraging their fiber networks. The next step in the process will be virtualization, which is already being deployed at the core of the network, but will eventually reach the RAN as well," concluded the Director of Business Development at CommScope Connectivity Solutions.
