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Why 5G Matters
Over the last month I undertook a detailed review of a new book in the Systems Approach series, 5G Mobile Networks: A Systems Approach by Larry Peterson and Oguz Sunay. Talking to people outside the technology world about my work, I soon found myself trying to explain "why does 5G matter" to all sorts of folks without a technical background. At this point in 2020, we can generally assume people know two things about 5G: the Telcos are marketing it as the greatest innovation ever (here's a sample); and conspiracy theorists are having a field day telling us all the things that 5G causing or covering up (which has in turn led to more telco ads like this one). By the end of reviewing the new book from Larry and Oguz, I felt I had finally grasped why 5G matters. Spoiler alert: I'm not going to bother debunking conspiracy theories, but I do think there is something quite important going on with 5G. And frankly, there is plenty of hype around 5G, but behind that hype are some significant innovations.
What is clear about 5G, technically, is that there will be a whole lot of new radio technologies and new spectrum allocation, which will enable yet another upgrade in speeds and feeds. If you are a radio person that's quite interesting–there is plenty of innovation in squeezing more bandwidth out of wireless channels. It's a bit harder to explain why more bandwidth will make a big difference to users, simply because 4G generally works pretty well. Once you can stream video at decent resolution to your phone or tablet, it's a bit hard to make a case for the value of more bandwidth alone. A more subtle issue is bandwidth density–the aggregate bandwidth that can be delivered to many devices in a certain area. Think of a sporting event as a good example (leaving aside the question of whether people need to watch videos on their phones at sporting events).
Lowering the latency of communication starts to make the discussion more interesting–although not so much to human users, but as an enabler of machine-to-machine or Internet-of-things applications. If we imagine a world where cars might communicate with each other, for example, to better manage road congestion, you can see a need for very low latency coupled with very high reliability–which is another dimension that 5G aims to address. And once we start to get to these scenarios, we begin to see why 5G isn't just about new radio technology, but actually entails a whole new mobile network architecture. Lowering latency and improving availability aren't just radio issues, they are system architecture issues. For example, low latency requires that a certain set of functions move closer to the edge–an approach sometimes called edge computing or edge clouds.
The Importance of Architecture
The high points of the new cellular architecture for 5G are all about leveraging trends from the broader networking and computing ecosystems. Three trends stand out in particular:
5G networks are architected much like modern public clouds, leveraging lots of related technologies like virtualization and microservices architectures.
The actual networking part of 5G is largely based on software-defined networking, the dominant paradigm for networking in modern data centers and clouds.
The entire cellular architecture has been disaggregated–that is, what used to be vertically integrated systems from a single vendor are now broken apart into components that can be realized using a selection of components from a much wider ecosystem of vendors, including open source components.
Now none of this matters to the end user unless it provides some compelling benefit to them. Fundamentally, I believe this new architecture will unleash a whole lot of innovation and we don't yet know exactly what apps will be enabled. This is precisely where the Internet succeeded around 25 years ago, when it was not yet obvious that it would become the dominant networking technology. It was the most general-purpose architecture out there, with the greatest flexibility to support new applications, and in the end the rich diversity of applications was what made the Internet a success. By contrast, the cellular network has historically been optimized for a few well-understood applications (voice calls, SMS, etc.) and it is only with 5G that it really becomes a general purpose platform for innovation. This is one of the reasons it can be challenging for Telcos to market 5G: they have to show us its potential when we (and they) don't yet know what the "killer apps" will be.
If you want to know more about the architecture of 5G, the application requirements that are driving it, and how it will enable innovation, you should go read the book as I did!