Decoding 5G beyond the Hype
5G promises to deliver higher speeds and support revolutionary new use cases, services and applications that connect people and things. According to the Gartner Hype Cycle for Emerging Technologies, 5G is near what it calls the "peak of inflated expectations." It has been getting a lot of attention in the media recently from Communications Service Providers (CSPs) rushing to announce commercial availability of the network to promises of futuristic applications being developed for both consumers and enterprises.
In reality, three distinct sections of the network will see changes as a result of leaping to 5G. These include the radio access network (RAN), the mobile core and the broader network.
Traditional networks require base stations to have its own computing and processing ability along with the associated power, cooling and routing functions. Since 5G will require large number of base stations to support high speed at a much higher frequency spectrum, traditional architecture may not be able to scale for 5G requirements at optimal cost. And without such a rapid and massive deployment, the sparse high-frequency 5G base stations will be incapable to accommodate the extraordinary increases in demand of data volume, service diversity and associated performance expectation. Hence CSPs are moving to Cloud (or Centralized) Radio Access Networks, otherwise known as C-RAN, which deconstructs base stations to lower cost, and improves performance and scalability by moving the baseband processing (the digital processing function of base station under traditional RAN architecture) to a centralized location.
The deconstruction of base stations (as shown above) to separate Remote Radio Head (RRH) and Baseband Unit (BBU) creates the need for a fronthaul transport network with a semi-proprietary Common Public Radio Interface (CPRI) or packet based e-CPRI used between RRH and BBU. Fiber is the underlying physical connection that will support this transition on CPRI or e-CPRI. Since its introduction in 4G LTE, fronthaul connections already began transitioning from heavy coaxial cables to fiber. Backhaul connections, anyway, are being transitioned from copper to fiber in a phased manner. The acceptability of fiber on both the backhaul and fronthaul networks necessitates the need for robust fiber planning & management. And fiber planning has to happen in conjunction with the Functional split guidelines driven by latency expectations defined by CSP for itself.
The placement of fiber optic lines has garnered renewed enthusiasm for getting deployed closer and closer to the customer in the new architecture. 5G will require both macro cells and small cells to have connections of some sort to wired high capacity networks. Although Fixed Wireless Access (FWA) is an option being trialed in areas where laying fiber is not practical or permitted, fiber is the best choice for serving the increased number of wireless serving points that 5G small cells will create.
The scalability problem in the mobile core is being addressed by migrating to the Next Generation architecture with Software Defined Networking (SDN) and Virtual Network Functions (VNF) principles. These changes in the core are laying the foundation for CSP to deploy services in an automated, simplified and flexible manner.
