The 5G evolution continues...
01 June 2019
Figure 1. Sprint massive MIMO antenna [Source-John Saw, Sprint CTO]
There’s a global race to be the first country to deploy 5G. Sarah Yost, Senior Product Marketing Manager at test & measurement expert, National Instruments explores some of the technologies behind the evolution and roll out of 5G…
This article was originally featured in the June 2019 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.
While all the major carriers in the US are making announcements of 5G support, two of them are particularly interesting: Sprint and Verizon. Verizon has announced that it will have 5G in 20 cities by the end of the year, using a 28 GHz network. Sprint has announced that 5G is live in 9 of its biggest markets.
The 5G technology that Verizon is taking advantage of is mmWave. It will deliver extreme speeds in the 20 cities where it is available for users who have a device capable of taking advantage of it. Sprint is in a unique position compared to other carriers, because of the spectrum that they have, 120 MHz of bandwidth at 2.5 GHz. They are the only operator that has enough bandwidth to do 5G NR and LTE at the same frequency – and they have made no public announcements regarding mmWave spectrum at this time. Sprint has taken a different approach and focused on deploying base stations that take advantage of MIMO.
Both of these technologies are 5G technologies, but the level and type of service they provide is very different. So, what does ‘5G’ mean for consumers who want to be early technology adopters? While all carriers will be rolling out 5G, in practice, the features and functionality available will vary from carrier to carrier for at least for the next 2 to 5 years. It is important to remember that it is still early in the deployment process for 5G. It took years for LTE to be deployed – and it could be argued that even today, it’s still not fully deployed. There shouldn’t be any expectation for a faster timeline for the deployment of 5G.
Figure 2. Multivendor 28 GHz 5G NR network demo at the Brooklyn 5G Summit
These initial deployments of 5G are an important milestone, yet 5G is about much more than making incremental improvements to streaming speeds and capacity. 5G has promised to revolutionise wireless communications – and, in turn, to revolutionise the world. What makes 5G different from the previous 4 generations is its focus on latency, device density and enabling deep verticals on top of 5G.
The majority of the deployments for 5G in the next two years will be for sub-6 GHz. There is still significant interest in mmWave, but to put it simply, mmWave is hard. It is hard for a lot of reasons: non line-of-sight scenarios, beam tracking, power consumption and manufacturability, to name a few. The progress made in the last five years for mmWave is significant, and it will continue to progress; however, the technology is simply not yet at the same maturity level as sub-6 GHz. The fixed wireless access use case for mmWave is compelling, but the mobility use case has yet to be proven viable. Even after all of the technological challenges are evaluated, the economics of mmWave may prove to be too costly to overcome.
For both mmWave and sub-6 GHz, carriers are pushing for a white box approach to hardware in their networks. This would lead to more flexibility on the carrier side to create an economical network – and it also opens up the hardware ecosystem for new levels of innovation, as well as custom hardware for specific vertical applications. The Open RAN Alliance (O-RAN) is investigating creating a standard interface between an RRU and baseband hardware. If an open standard exists for this, new and smaller vendors have the opportunity to create hardware solutions tailored to specific application requirements. CPRI is an example of a previous attempt to use a standard interface. Unfortunately, each vendor ended up customising bits and pieces of their CPRI interface, so that by the time hardware with CPRI was actually deployed, it was not interchangeable between vendors.
With a more white box approach to building 5G networks, verification of these solutions becomes critical. There needs to be a golden reference to test multivendor solutions, to verify algorithmic performance and signal quality. NI, Radisys and CommScope recently demonstrated a multivendor commercial gNB at 28 GHz, working with a 28 GHz Test UE designed by NI, as a proof of concept of what this type of system will look like. The gNB was built with an Intel FlexRAN baseband, Radisys protocol stack and CommScope RRU. The gNB communicated over-the-air with the NI Test UE, which provided real-time L1 measurements, which can be used to verify the gNB is working properly and measure the network’s performance. A test UE can also be a helpful tool for lab and field trials. Since it is software defined, unlike a silicon based MTP, performance information is displayed and logged for debug and optimisation.
Figure 3. 5G features timeline versus use cases
5G evolution and 6G
The line between deep verticals for 5G and 6G technology can be fuzzy. Some of the latest application trends in wireless communications research include V2X (vehicle to everything), augmented and virtual reality (AR/VR), machine learning/artificial intelligence (ML/AI), non-terrestrial networks and terahertz frequencies.
Terahertz frequencies for communications and sensing is still in its infancy and clearly a 6G technology. The others could be argued either way. V2X and AR/VR have been closely linked to 5G, and the KPIs written into the 5G spec can address these applications well. Addressing ultra-reliable low latency communications (URLLC) is advancing in the 3GPP standardisation processes, as well as V2X and non-terrestrial networks. Whether they will be completed in release 16, or whether they will be pushed to release 17 and beyond, will depend on the progress that is made. Outside of the standards, work is being done to figure out how to slice networks to deliver specific KPIs to specific applications in an on-demand fashion. Research into edge cloud computing is being done to address URLLC needs.
This is an exciting year for 5G, as consumers are starting to be able to take advantage of the latest technology. But it’s just the beginning of being able to realise and harness its potential. When LTE was first being deployed, no one imaged how it would change our world, with services like Uber. It’s exciting to speculate about how 5G is going to change the world – and even more thrilling to watch as it starts to unfold.
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