By Dr. Claudio Mazzali, senior vice president & CTO – Corning Optical Communications
In times when headlines are making the most of technology buzzwords, it is essential to filter some of the noise and to focus on key drivers behind the ongoing transformation in our industry. Without a doubt, 5G has a primary position within the rank of current buzzwords, but its importance and impact go beyond wireless services and expand to the entire telecom/datacom infrastructure. In other words, 5G is the catalyst accelerating evolution and connecting different spaces in our industry.
It is not uncommon for industry representatives to refer to 5G as a fixed wireless solution, or a millimeter wave technology, or an IoT framework, or even a low latency enabler. Although all of these are indeed elements of 5G, this next generation of wireless is better defined simply as a QoS (quality of service) that meets several KPIs (key performance indicators) as currently determined by members of our industry with the 3GPP organization. These KPIs outline performance requirements like 100 Mb/s user experience, 10 Mb/s per m2, latency <1ms, etc. The reality behind these targets is that they will not be met simultaneously and everywhere as 5G starts. Even more important is the fact that carriers will have to use a combination of architectures and technologies that can be very different depending on both the services that will be initially targeted, as well as the characteristics of the specific deployment.
For instance, the 5G capability to incorporate higher frequencies, including millimeter waves, can enable a carrier to provide short distance, high capacity direct wireless links, which can help replace the copper bottleneck in some final connections to subscribers. A different scenario may instead leverage the 5G ability to support lower radio network latency to enable fast interactive services like remote driving in geofenced areas. These are a few of the examples for exciting new services potentially enabled by the 5G QoS, and it will take a while until we see all these potential services being enabled and offered simultaneously. Even with some people questioning how solid the business case for these new services may be, carriers across the world are consistently moving towards more investments in infrastructure to minimize any risk of the network as a bottleneck for this exciting future.
From a high-level perspective, in order to meet the 5G requirements, service providers have essentially three knobs to use:
a) Increased and better utilization of spectrum
b) Equipment with higher spectral efficiency (or how many bits per second of data can be modulated in a Hz of spectrum)
c) Network density (or number of antennas per unit of area)
Once again, different carriers and different deployments will optimize these knobs in different ways, but historically the densification has been by far the most efficient contributor for wireless capability, with an impact roughly 100 times higher than the other two. Even with today’s improvements on wireless equipment’s spectral efficiency and current actions by many governments to make more spectrum available, the gap in performance expectation from 4G to 5G is such that it is widely accepted in the industry that a significant increase in network density is required to bring true 5G to reality.
In addition, carriers across the globe are realizing that this need to deploy more antennas (both macro and small cells) and antennas closer to customers makes it almost an obvious choice to build an optical access network with capacity and architecture optimized to handle all traffic independently, if final connection will be through a fixed or a wireless connection. This convergence of optical + wireless in the access network is a trend that is now being significantly accelerated by the 5G catalyst.
It is true, however, that while steady expansion of fiber coverage is observed in many countries, barriers still exist including the lack of policy on access to poles in high density areas, and the high cost of deploying infrastructure in geographically challenging areas. Moreover, there are ongoing debates on the optimum approach to bring the optical signal to all these new radios. In some cases, carriers and system vendors are trying to leverage the evolution of the PON (passive optical network) architecture broadly used in FTTx deployments (in particular NGPON2), even if that ends up requiring a reduction in the split ratio. Another line of thought that seems to be dominating the initial deployments is realizing that in locations where there is no fiber installed yet and new cable has to be deployed anyway, a point-to-point architecture may provide a more robust optical infrastructure. This is less dependent on the evolution of the electronics and capable of bringing that optical capacity to the edge of the network, not only for 5G radios, but also for what may come next.
It is becoming clear for carriers that this is a unique opportunity to make the last investment in network infrastructure, thus reducing the risk of more civil work cost for future upgrades. These are key focus areas where the industry needs breakthrough innovation. Solutions should not be adapted, but instead designed from the beginning with a converged architecture in mind, even enabling the co-deployment of PON and Pt-to-Pt such that cost and speed of installation are significantly reduced.
Moving even further into this concept of 5G as a catalyst for broader transformation of the telecom infrastructure, we can now see that this new converged optical-wireless access network is also the high capacity fabric connecting the computing infrastructure being built in the hyper scale datacenters. It is with the capable computers we carry in our pockets and the edge computing capabilities that are starting to be implemented by carriers. This combination of centralized and distributed computing capabilities is a silent evolution with potential to be historically even more impactful than the transition from mainframe computers to personal computers from few decades ago - a transition that created industries and changed the world.