When a number of services are combined within single access networks, it is referred to as fiber network convergence. This means that multiple or all types of communication services are delivered through a single pipe. A fiber-to-the-home (FTTH) network has for example a wide footprint that is ideal to support fast-growing mobile apps including Centralized-RAN front-haul, WiFi and small cell backhauls, and distributed antenna systems (DAS). Service providers would be able to enter new markets, offer innovative services, adopt new business models and deliver a wider range of services through fiber network convergence.
Fiber network convergence is mainly driven by user demand, a service provider's capabilities and enabling technologies being developed. Huge service providers have wireless and wireline operations, so it makes business sense to converge these onto one network, thereby maximizing the utilization of assets. There have been many cases where FTTH networks were installed, only for the same street to be dug up a few months later to lay fiber for cell sites. This is both disruptive and wasteful. Network convergence enables one build to be utilized for several service delivery platforms.
For smaller municipalities, utilities and telcos with limited budgets, adding revenue streams, selling to multiple market segments and mitigating the risks in the business are often critical aspects of network convergence. One city may have simultaneous projects for high-speed internet in residential areas, WiFi in the city center, security cameras and traffic lights, and fiber for government offices and schools. By converging these onto one fiber network, these projects now have greater economies of scale, more funding sources and more stakeholders.
The FTTH networks will have spare capacity that could can be sold as wavelength services or "virtual dark fiber" that would cost less, yet can be deployed faster than laying fiber point-to-point. Many FTTH networks only use two, or at most three wavelengths for video overlay, GPON upstream and Gigabit Passive Optical Network (GPON) downstream. The huge C/DWDM spectrum of wavelengths are unused, thus offering a path for evolution and growth.
The same fiber strand can be used by service providers while residential GPON and cell site traffic are kept on different wavelengths. Passive C/DWDM modules are used at both sides of the fiber to separate or combine the different wavelengths. An alternatively would be to implement the connectivity at the closures and hubs to route the traffic appropriately, while keeping traffic on separate fiber strands.
Using dark fiber for wireless applications is often a costly and long process. As cell densification is accelerating rapidly and with 5G in the near future, fiber availability could become a bottleneck. Demand for fiber-based front-haul and backhaul will keep on increasing. This aspect of network convergence needs greater foresight and collaboration.
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