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Almost weekly, you see an announcement about the 5G rollout in yet another city or region, from the USA to Germany to South Korea. Verizon expects three-fourths of the phones they launch in 2020 to be 5G, and AT&T has announced they are on track for nationwide 5G coverage in mid-year 2020. The rollout continues apace, with more users enjoying fewer bottlenecks, more capacity and new kinds of network deployment for the innovations in your applications.
We’ve already updated you on the state of the 5G nation and on spectrum in 5G. In this post we’ll describe what’s behind the 5G rollout.
What’s on the 5G roadmap?
Figure 1 shows the standardization timeline set out by the 3rd Generation Partnership Project, or 3GPP, the body that oversaw the development of 3G UMTS and 4G LTE standards. 3GPP is also defining 5G New Radio (5G NR), the new global standard.
Figure 1: 5G roadmap. Click to enlarge.
The Rel-15 specification includes features that will support enhanced mobile broadband (eMBB) for immersive user experiences. Carriers spent most of 2018 on interoperability and development testing (IODT) and field trials. This year, they have been rolling out, or commercializing, Rel-15 features in the bands below 6 GHz and the mmWave bands above 24 GHz.
Which will be the first use cases to run on 5G? For the next couple of years, you’re likely to see 5G-related news about shorter video download times on smartphones and performant eXtended reality (AR/VR) over the WAN. eMBB also extends to connected laptops; customer premise equipment (CPE) for home broadband gateways; private, indoor 5G networks.
And even as commercialization is underway, 3GPP continues work on Rel-16 and Rel-17+. In other words, there’s plenty more 5G NR to come.
But note the long arrow at the bottom of Figure 1. For many, the surprising thing about the roadmap is that Long-Term Evolution (LTE) will remain an integral part of 5G rollouts for some time yet.
What is the role of LTE in 5G?
LTE, long associated with 4G, continues to evolve.
In the early stages of rollout, most 5G networks will have a limited local and global footprint. LTE will provide a layer of wide coverage in the initial, non-standalone (NSA) operation of 5G networks, as shown in Figure 2.
Figure 2: Non-standalone (NSA) operation. Click to enlarge.
NSA combines the Evolved Packet Core and the radio network of 4G with the mmWave frequencies and/or sub-6 GHz bands of 5G NR. Because 5G modems are designed for dual connectivity, they handle data, control and mobility management over the LTE link, and data over the 5G link.
How do LTE and 5G NR interoperate?
Figure 3 depicts how dual connectivity — in this case, to a mobile device — takes advantage of years of investment and development in Gigabit LTE. The result is representative of the kind of coverage possible in 5G eMBB.
Figure 3: LTE supplementing 5G NR. Click to enlarge.
Dual connectivity makes gigabit-speed experiences possible anywhere, capitalizes on the ubiquity of LTE to provide Voice over LTE (VoLTE) and supplements the mid-band and mmWave reach of 5G NR. It allows carriers to roll out high-value features without the need to wait until 5G is fully commercialized.
Once carriers are ready, they will be able to switch to the 5G NextGen core network in standalone (SA) operation, as illustrated in Figure 4.
Figure 4: Standalone (SA) operation. Click to enlarge.
SA operation supports the 5G architecture from end to end, without the layer of LTE coverage from the non-standalone model.
In the NextGen core network, network functions virtualization (NFV) provides basic functions, and software-defined networking (SDN) controls them programmatically. Voice over New Radio (VoNR) replaces VoLTE for carrying voice traffic.
What’s the news for developers?
As I’ve mentioned, it will be some time before you see any commercialized 5G standalone networks. But that doesn’t mean that we’re not studying them.
Most of the talk about higher speeds in 5G focuses on the downlink and how those speeds can bring about innovative user experiences. That’s true, but it’s also true that uplink is equally important to app developers. Knowing the uplink performance you can realistically expect from 5G networks gives you a head start on building new apps and improving existing ones.
Qualcomm Technologies, Inc. has added detailed uplink simulations to our 5G NR Network Capacity and User Experience platform. The platform is designed to deliver quantitative insights on the expected real-world uplink performance and user experience of 5G NR and Gigabit LTE devices. Have a look at our recent simulation study. It showcased an uplink capacity increase of nearly 3x when migrating from an LTE-only network, with a mix of LTE devices of various capabilities, to a 5G NR network.
That’s an uplink capacity boost worth looking forward to.
Keep an eye out for more posts in this series on 5G. Next month I’ll look under the hood of our 5G modems.
Snapdragon is a product of Qualcomm Technologies, Inc.
