5G Standalone Architecture and Features

What is new radio?

The need for high
throughput for the rapidly evolving bandwidth-hungry data services has been
identified quite some time ago, resulting with a lot of research and
development going into new radio concepts. The step from CDMA-based UMTS to
OFDM-based LTE was aided by the already well-rooted (also OFDM-based)
technology of WiFi. But it was not only the choice of that particular transmission
and multiplexing technique that made the 4G radio more efficient than the
earlier 3GPP systems. Over time, a big number of LTE Radio Features has been defined
and deployed, significantly adding to the transmission speeds.

Carrier Aggregation. A fairly straightforward idea… The LTE radio resources have pre-defined “sizes”, placed on a part of the radio spectrum of a certain width. Why not bunch these pre-defined radio resources, creating therefore a much wider radio resource, allowing for a lot more information to be transported to/from a certain device on 2, or on 3 component carriers?

Dual Connectivity. A similar concept, really… Allocate resources for a particular device from two radio network “towers” simultaneously, enabling a double throughput.

Multiple Input Multiple Output, MIMO. Why not take a number of transmitters or receivers (from the same “tower”) and use them to transport information to/from a certain device? If the transmitters are satisfactorily far apart from one another (we are looking at centimetres here) the transmitted signals will be distinctive enough for the receiver to interpret them separately.

These, and other radio
network features have been developed in the process of the evolving the LTE
radio. Basic LTE (3GPP R8), then LTE Advanced, LTE Advanced Pro: more carriers
that could be aggregated, more antennas in the MIMO antenna array… As the
numbers grow, so do the throughputs.

New features of the New Radio

So, how can the 5G New
Radio improve even more? Can we increase the throughputs with some smart new
solutions? The obvious first step is to continue with the evolution of the
previously defined features… More Carrier Aggregation? Yes! Wider carriers?
Yes! Dual Connectivity with LTE radio? Yes! That would be Inter-Rat Dual
Connectivity… Even more antennas in the MIMO antenna array? Yes! That would be Massive
MIMO…

In other words – yes,
the 5G New Radio gives increased throughputs – but that is really a
continuation of the 4G radio’s evolution path, not an actual breakthrough new
concept. On top of that, though, there exists a rather obvious solution for
increasing throughputs: adding more frequencies to the defined licensed radio
spectrum. Standardising more allowed resources on the radio spectrum can be the
biggest throughput-booster. The only problem is that the more attractive parts
of the spectrum are already in use for other purposes, which leaves the ITU-R
with the less attractive parts of the spectrum to open up for 5G usage. This “less
interesting” part of the spectrum is higher up, where the frequency of the wave
increases (and its length shortens), making the wave less resilient to
obstacles on its way. What’s worse, the shorter the wave, the smaller objects
become obstacles – from mountains being an issue for the traditional GSM
carriers to wet leaves becoming a problem once we start using higher parts of
the spectrum currently defined for LTE usage.

An ITU-R congress in October
and November this year (in Sharm-el-Sheikh, Egypt) will finalise the spectrum
allocation for 5G. Currently it is expected that the newly allocated frequencies
might go all the way up to 100 GHz, meaning we will be using millimetre waves
(mmWaves) to transport data over the 5G NR. That high up in the spectrum we can
only expect reasonable signal propagation for very short distances, but within
this area a significant throughput boost will be achieved.

And that is really the major improvement the 5G NR will bring – additional radio spectrum to increase the capacity. All the rest of the NR features are basically a continuation of the LTE evolution. It just seems 3GPP realized that calling the next evolution step “LTE Advance Pro +” is a bit of a tongue twister – and ended up call the 5G new radio “New Radio”. Which might become awkward one day, when a 6G system is born New Radio might be old technology…

• 5G-training
• 2g, 3G and 4G training

If you already know – that’s great! It means that you don’t have to read the rest of this article. Perhaps a coffee break instead? But if you don’t know about the various options, hopefully this text will explain what they are all about!

5G deployment options

In short, these options describe different combinations of base stations (eNBs and gNBs) and core networks (Evolved Packet Core, EPC or 5G Core, 5GC). Obviously, an operator will not replace the 4G network (eNBs + EPC) with a 5G network (gNBs + 5GC) overnight! There will be a migration that can follow different paths.

Sometimes you’ll hear about Option 1 which oddly enough is not 5G at all. In fact, Option 1 is good old 4G with eNBs connected to EPC and it is there more as a reference or starting point.

Option 2 is more exciting! This refers to gNBs connected to the 5GC. True 5G if you will, with support for all the fancy 5G features and use cases. But still a little into the future at the time of writing this article.

Option 3 is likely to be the first 5G step for many operators. This means keeping the EPC and legacy eNBs, but adding gNBs in the radio network. Those gNBs add more New Radio (NR) capacity, but they cannot work on their own. The depend on having an eNB as a companion and for having a control plane connection to the core network This setup is therefore referred to as Non-Stand Alone (NSA) mode.

Option 4 is “the opposite” of Option 3. The core network is 5GC and in the radio network there are gNBs – but also eNBs in Non-Stand Alone mode meaning that they do not work on their own. They need to have a gNB as a companion.

Option 5 is a bit odd, perhaps? It is the 5GC but 4G eNBs in the radio network, although the eNBs have the new NG interface towards the 5GC. The use case for this might not be obvious, but maybe we can think of an operator who does not see an immediate need for more radio capacity but still wants to benefit from new functions in the 5GC e.g. better support for virtualization and network slicing?

Option 6 is easy – it does not exist! At least not anymore! Which brings us to…

Option 7! What combination is left? It is the 5GC with eNBs plus additional gNBs in NSA mode. Perhaps the operator in Option 5 realizes that more radio capacity is actually needed, and therefore adds gNBs in strategic places in the network.

Are the 5G Options clear?

Hmm, did anything become clearer? Perhaps a little? But actually, all the nice benefits we get from possible interworking between 4G and 5G come at a price in the shape of many deployment options and possibly some brain pain. But if you like crosswords and sudoku – you’ll enjoy 5G!

• 5G-training
• Network-slicing
• 5G new radio
• 5G core network architecture
• 2g, 3G and 4G training

So I’ll tell you.

By the way: I’m Martin, and I’ve been a telecom technical instructor since the last millennium. Or counting in a way that may be more relevant to you: since 2G. For a long time that meant teaching special telecom things that only existed in the telecom world. With the advent of Voice-over-IP and SIP, my telecom world started crashing with datacom, and that crash only continued when virtualization entered stage. Suddenly telecom, datacom and general computing was all mixed up!

So, since a couple of years, we’re in this chaotic, mixed-up world.
How about I actually go on with the story of network slicing, then?

Network Slicing

First of all: network slicing is not new. Much like many (some might even say all) of the constituent parts of the 5G revolution, it has been around before, and the new thing is sticking all these parts together instead of keeping them apart. Perhaps it was really chaos before, when we had so many different technologies that didn’t interact, and now when everything starts to get connected, it’s actually bringing order to the world? Let’s stick with that story for a while, instead. Sounds more positive.

Technical Part

Technically, network slicing is very comparable to cloud technology. And to not make things even vaguer, by cloud technology I mean hardware resources that can be used by many customers, but are not dedicated to customers over time. Example: Dropbox. You get access to a hard drive somewhere, that is physically shared with others, but you never see them. Or a server you rent from Amazon to run your web page on – the physical server probably has other customers as well, but you never see them. Or a fiber optic cable connecting Europe with North America. It’s extremely likely you’re not alone on this cable, but again: you never see the others. In all these examples you can easily change the service (increase or decrease resources) without having to care about any physical reality. Buy more storage space – buy another virtual web server – add more bandwidth. All at the swipe of a credit card!

One way of phrasing this is to separate physical networks from logical networks. Even though you share all the physical aspects of this world (hard drives, servers, cables) with others, you have your own logical hard drive, your own logical server, and your own logical transatlantic connection. Logical things that don’t interfere with other customers’ logical things. Logical is a word being used a lot here, so you have to accept that, but it’s also a word that sounds more vague and nebulous than it is. Like “virtual servers”, “ghost computer” or “imaginary number” the words themselves almost makes it worse, don’t they? In our case a “logical” resource given to you just means that during a particular span of time you are given access to a particular portion of a physical resource. That portion is dedicated to you during that time, but may be bigger, smaller or not yours at all at a later time.

So what happens if you connect all your logical things? You connect your logical hard drive (a portion of one or several physical hard drives) to your logical server (software using a portion of the CPU and RAM of a physical server), and then connect that server to your logical network connection (a portion of the bandwidth available in a physical network connection). And then perhaps add another logical server on the other side of that logical connection. Well, then you have your own network to play with, that others can’t see. Then again, others could (and will!) do the same thing and connect their logical servers/hard drives/cables into a network that you can’t see.

Remember that this is all running on the same physical hardware. You and those mysterious “others” all share the same real-world infrastructure. It’s almost as if we had “sliced” that real world of hardware into logical slices containing servers/hard drives/cables and given one slice to you and one slice to me. Yes, let’s do that, let’s call them slices. Because if we do, we have performed “Network slicing”. Network slicing is the act of having one set of hardware – one physical network – serve several customers or uses, each slice being a “complete” network, but also not being aware of the other slices.

You can also see this as the next step up for logical things – remember those? Logical things were portions of hardware resources. Portions of hard drives, servers and cables. A logical network (or network slice) is then a portion of a physical network, including portions of the resources available (storage, CPU, network). And just like you could change your allotment of logical storage or logical bandwidth, so can your whole logical network (or network slice) change over time. More customers  – grow with a few extra nodes and more bandwidth. Early morning – shrink your resources, because everyone is sleeping. All at swipe of your metaphorical (or real!) credit card.

5G Use Cases

In 5G, network slicing is often used in the context of the different use cases. There are currently three well-known 5G use cases:

1. Super-fast Internet (eMBB or extreme Mobile BroadBand)
2. Super-good network connections (URLLC or Ultra-Reliable and Low-Latency Communication)
3. Internet-of-Things (mMTC or massive Machine-Type-Communication).

These use cases all present different networking challenges and the networks that provide them can reasonably be expected to look quite different. But instead of building three different networks, operators build one. A flexible one, though, that can be sliced up into slices perfectly matched for the use cases you need – and when you need them!

How to slice?
If you wonder exactly how you slice a network into pieces, the answer is either very short or very long. I’ll give you the short one: NFV and SDN. And if you want to learn the long answer, just come to us at Apis IP-Solutions and ask. We’d love to tell you!

Watch our YouTube Video about Cloud, SDN and NFV training

[youtube]https://youtu.be/6jIDRNTe-LI[/youtube]

Do you know exactly what 5G is? I mean, what it really is? Most sane persons should answer “probably not” to this question. But there is help to be found, here at Apis IP-Solutions. Because a while ago, we didn’t know either! Is it a technology? A business case? An era? Or just a hype?

5G Course

We felt the same despair that we believe a lot of people in the telecommunications business feel today when the topic of 5G comes up. Perhaps even you?

We set out to create a 5G Course (5G sytem overview ), for engineers, that would answer these questions as well as give technical descriptions of whatever there is to describe. And let me tell you: we were surprised by how much there was to describe!

Sneak Preview

So, let me give you the sneak preview: 5G is described by many organizations around the world, but when it comes to actually standardizing technology, it’s still 3GPP that does the heavy lifting. Just as with 3G and 4G. So in this new 5G course we cover how vendors, operators and special-interest organizations describe 5G, but the foundation for technical descriptions comes from the 3GPP specifications.

So: 3GPP again. This could lead you to a couple of (incorrect) conclusions. How about “So it’s just another G, just like the transition from 3G to 4G”? Or “So we’ll get higher mobile bit rates than 4G, I guess that’s cool”? Wrong. The 5G system changes more than that.

5G is More

First of all, it does change those things. We do get higher mobile bit rates. But ITU themselves, the global United Nations body that “ordered” the world to build 5G, writes: “[5G] systems will differentiate themselves from [4G] not only through further evolution in radio performance, but also through […] end-to-end flexibility […] softwarization […] SDN, NFV and cloud computing [and] network slicing”.

This is why we in the new 5G System Overview course cover not only the new radio technology of 5G. Of course we do cover radio, with all the new RAN configurations including e.g. dual connectivity (both all-5G and different mixes of 5G and 4G), offload on unlicensed spectrum, 3GPP/WiFi aggregation, non-3GPP access, C-RAN (centralized Radio Access Network) and standalone vs non-standalone deployment.

And equally natural we spend a lot of time describing the all-new 5G core (5GC) architecture and all the new functions therein. Here we learn about all the new ways in which data connections (PDU Sessions) can be set up, modified, split and handed over, in ways that was never possible in previous mobile generations. We also learn about how HTTP takes over the role of protocols like Diameter and GTP.

But we also learn about NFV, virtualization and SDN (Software-Defined Networking) in 5G. We explain “Network Slicing”, a crucial 5G concept, which really requires NFV and SDN to work. We cover MEC (Multi-access Edge Computing) together with the 3GPP concept of LADN (Local-Access Data Network) used to run services close to customers to lower latency and gain local relevance.

Conclusion

Do you feel like, Yes, I want to know more about the 5G Course?

If you come to our “5G System Overview” you will learn what 5G is, why it is and all the ways in which 5G represents such a major shift of thinking, compared to 4G (and 3G and 2G). Welcome!

We hope to see you soon!

The Apis IP-Solutions team

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