While presenting on the topic of “5G” recently, I was asked: “Why are we making everything so complicated?” In that moment, as I surveyed the audience of principally telecom industry types – of which I proudly count myself as a member for the last 20-plus years – I was struck by a couple of epiphanies. The first was, we really are presenting this 5G stuff all wrong, and the second, is this fundamental disconnect possibly the biggest challenge facing telecoms today? Let’s be clear, 5G will not be about complicating anything. First and foremost, and before I throw some 5G boilerplate at you, 5G will be about simplifying things and 5G will be about building essential flexibility into a system that is about to be hit by the most diverse set of requirements in any wireless generation.
Now for that boilerplate promise. It is still early days in 5G, but already forums have formed and some consensus is converging on requirements and timing. Arguably, the two high-level requirements most often cited are a 1,000 times improvement in peak data rates (on LTE 2010) and a major reduction in end-to-end latency to fewer than 5 milliseconds. These requirements, and others like them, are important but really only tell a part of the 5G story. Perhaps a better way to understand 5G is first through a historical lens. It is grounding to reflect that this journey began a little over 20 years ago with the proliferation of GSM. In those days, peak data rate support was 9.6 kilobits per second. Today’s LTE systems have improved upon that metric by 100,000 times, so in that context the 1,000 times goal of 5G would seem quite reasonable. Of course, 2G was not designed for data, it was designed really for only one thing: basic voice communications. The bar was raised with 3G, a specification that supported a couple of things, namely voice and the beginnings of mobile data. Taking that further was 4G, with the first real system designed principally to support video.
It is this evolution that has driven the 100,000 times change. It is this services roadmap that has also driven latency reduction on a parallel path. At the simplest level, 5G will certainly be about more of this. However, the true diversified 5G challenge is a lot more interesting.
In 5G, it will no longer be about supporting just a few things. It will literally be about supporting everything – a wireless world that is the “Internet of everything” – as the first generation to target the array of verticals markets that in themselves will define the IoE and its many millions of yet-to-be-imagined applications. That support is the real 5G challenge.
Think about it, what do an automobile and a thermostat have in common? They are all part of the IoE. So, how will 5G go about tackling the challenge of everything?
Think flexible. Think simple. Think new twists on solid old ideas.
Building 5G will start on a foundation of established IT thinking. The cloud, virtualization and programmable networking (aka software-defined networking/network functions virtualization) will provide the cornerstones. These technologies inherently deliver flexibility and, at least through the eyes of any IT professional, are a lot simpler than the legacy approach of telecom. However, 5G will take these technologies to new levels and depths of integration and in so doing will shape the 5G specification that will emerge tomorrow.
SDN/NFV in telecom is a hot topic today, but where we are now only scratches the surface of its original vision. The current focus of work in this area is primarily total cost of ownership and operating expense reduction through switch hardware commoditization and the efficient relocation of a subset of network functions.
In 5G, SDN/NFV concepts will be pushed much further, returning to the original value proposition of enabling true architectural innovation. In 5G, it will not simply be about virtualizing the network functions, but entirely changing its inner workings. Network evolution will be the frontline in the realization of many 5G requirements (e.g. ultra-low latency). Today’s Internet is simply not designed to support low latency. However, through programmable networking, new, more-efficient approaches will become possible.
In 5G, virtualization will touch every element in the system spanning backhaul, fronthaul and radio access. It is within this flexible, dynamically configurable fabric that system resources will be optimally and instantaneously orchestrated to deliver the next generation experience to end users.
So what about the radio technology? For so many generations a single acronym has provided the generational definition. In this respect, 5G will be different. There will not just be one radio and one new acronym, depending on how we look at it, there may be several.
The best that can be said today is that there will be at least three radio access technologies or modes spanning bands above and below 6 GHz. This may be realized in a standalone or flexible “unified” structure. Arguably, it might be said that there will be as many as six, if we are being fair and acknowledge the next generation unlicensed Wi-Fi initiatives that are already underway (802.11ax, ay, ah). A standalone approach has been adopted in IEEE, and cellular may or may not follow. Regardless, this boundary between licensed and unlicensed is only set to become more blurred as we move forward.
Two licensed band cellular definitions are expected below 6 GHz. One will be something of an evolution of OFDM purposed for coverage support and optimized in areas such as latency, energy, spectral containment and, of course, throughput. The second will be especially tailored for IoE support, but it is unlikely that it will be based on OFDM. OFDM is great for video, but in the IoE world of billions of random accesses, its synchronization requirement is a severe handicap amongst others.
The third high-capacity solution will be provided above 6 GHz in the so-called millimeter wave bands that start around 30 GHz. This is probably where there is the greatest industry debate going on at this time. Regardless of the final outcome a few common observations can be made. This radio may or may not be based on OFDM. A single carrier-based approach is more likely to be selected. Simply stated, in moving to higher frequencies and narrower beams many of the benefits of OFDM such as MIMO integration and higher-order QAM schemes diminish and further PAPR (power) becomes a handicap. So, it is fair to expect something new here as well.
I introduced this piece with a reflection on how perhaps this move on the path to 5G might be the biggest challenge facing telecoms today. The move to 5G will be a profound transition for telecom. When it emerges in the mainstream circa 2020, the business models and processes that will accompany it will be more aligned with those used in IT circles today. This will be an adjustment for an industry accustomed to a familiar way of working. Beyond technology, that is what will make 5G different. It will be about nothing less than an industry transformation.
In two follow-up articles we will explore both the 5G network and radio aspects in more detail.
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