By: Doug Haluza, Chief Technology Officer, ZenFi Networks

ZenFiCurrently, there are more mobile-connected devices than people. The Internet of Things (IoT) will demand ever more network capacity. Mobile data traffic generated by these devices is predicted to increase nearly tenfold in the next five years. To address the explosive capacity demands of mobile traffic while keeping operating expenditure (OpEx) and capital expenditure (CapEx) in control, operators are virtualizing the Radio Access Network (RAN).

At ZenFi Networks, simplifying the deployment process is at the heart of our dark fiber network solutions. Our purpose-built network leverages network reach and colocation infrastructure to support the wireless network densification, bringing more small cells, Distributed Antenna System (DAS) remotes, macro site Remote Radio Heads (RRHs), , and Wi-Fi access points closer to the user. This is key to enabling ubiquitous connectivity. Our integrated network enables solutions such as virtualized RAN (vRAN) or cloud RAN (cRAN), which is the next logical step in reducing cost and enhancing overall connectivity for end users. While collocating baseband processing units (BBUs) for Distributed Antenna Systems (DAS) substantially improves utilization, each unit still needs to be able to process its individual peak traffic load. By virtualizing BBUs in a dark fiber connected cloud, operators only need to provision combined computing resources to meet the aggregate peak demand.

Virtualized RAN is the move from base station hoteling of physical BBUs to virtual BBUs leveraging commonly available cloud computing server hardware. Through virtualization of BBUs, operators now have the ability to allocate processing resources within a centralized baseband unit pool to various virtualized base stations. Resources can be dynamically adjusted in real time based on each virtualized base station requirements as well as fluctuating demand. Through aggregation of small cells and virtualized RAN on the ZenFi network, providers can support the rising capacity demands of mobile traffic, while providing scalability and cost-efficiency through consolidated, streamlined functions. Virtualized RAN generates an easier way to maintain complex systems, while also significantly lowering compute, power, operational, and real estate costs.

While vRAN addresses current capacity issues, providers must also maintain Quality of Service (QoS). Ensuring consistent QoS can be achieved by deploying Common Public Radio Interface (CPRI) links between the BBU and Radio Remote Unit (RRU) at the antenna. CPRI testing of the physical layer is needed to support Fiber-to-the-Antenna (FTTA). To accommodate vRAN, test vendors such as JDSU and EXFO have successfully “virtualized” CPRI testing as well as the Passive Intermodulation (PIM) test set for CPRI Remote Radio Heads (RRHs). CPRI test sets simulate a BBU to test the RRH; this is now enabled with software in the test set (i.e. a virtual BBU), which simply needs to emulate the BBU communications via CPRI protocol. Rather than disconnecting the coaxial cable at the top of the tower to insert a test set for radio frequency (RF) sweep testing, virtual PIM testing sends test signals to RRHs and analyze return signals over the fiber to measure PIM. Virtualization of network service testing is now faster and simpler than ever before, nearly eliminating the need for tower climbs.

The ease with which we are able lower costs, increase capacity, and maintain high-performance networks through virtualized RAN on ZenFi Dark Fiber is nothing short of revolutionary. As mobile data proliferates, and mobile traffic continues its exponential growth, operators and vendors will continue to lean more heavily on mobile carrier network virtualization to overcome capacity demands and keep OpEx and CapEx in check. Moreover, with the growth of Software-defined Networking (SDN) and Network Functions Virtualization (NFV), it will be exciting to see the next evolution of vRAN application and integration.

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