What are standalone and non-standalone 5G networks?

For many people, 5G is probably just another generation of mobile networks with some additional features. Let’s face it; we see a new generation of mobile networks nearly every ten years, and now that we already get reliable mobile broadband speeds with 4G, do we really need yet another upgrade? It is not really a quiz question, but the answer may depend on what you want to use 5G for? One thing is for sure that as the years pass by, you are likely to benefit from 5G either directly or indirectly. The earlier mobile network technologies mainly focused on voice and text, and later with 3G and 4G, we got into a world where mobile broadband could be seen as a potential alternative to fixed broadband. While 5G can also do all that, that’s not really what 5G is all about. 5G is a very versatile technology that can cater to a wide range of uses cases with very different needs. For example, 5G can provide connectivity to IoT devices that require very low data rates, e.g. 50 kHz, but it can also provide average mobile broadband speeds of 150-200 Mbps to a laptop. This flexibility of operation doesn’t come without complexity in the network architecture. There are two deployment models, that allow a mobile operator to migrate from 4G LTE to 5G NR networks.

What is NSA and SA in 5G?

Let’s get the acronyms sorted out before diving into the details. NSA and SA are two deployment modes of 5G, where NSA stands for non-stand-alone 5G operation, and SA stands for stand-alone 5G. In simple terms, stand-alone 5G is a full end-to-end 5G network, whereas non-stand-alone is not. Mobile broadband is one key aspect of 5G for consumers, which NSA can enable; however, futuristic use cases require standalone 5G.

What is non-standalone 5G?

The non-standalone (NSA) deployment model of 5G NR is where 5G services are delivered through a combination of 5G and 4G networks. NSA requires an existing 4G LTE infrastructure to enable 5G connectivity, which means having to rely on some parts of the 4G LTE network to connect 5G devices. This option can be seen in multiple ways. It is a cost-effective option as it allows mobile operators with existing 4G LTE networks to basically “sweat their assets” and launch 5G quickly without investing in an end-to-end 5G network. But there are also some limitations in terms of the use-cases that can be enabled by 5G NSA. Overall, 5G networks can enable enhanced mobile broadband (eMBB), massive machine-type communication (mMTC) and ultra Reliable Low Latency Communication (uRLLC) use case categories. If the key service a mobile operator wants to focus on is high-speed mobile broadband, then non-standalone is a quick win for them as it gives them a swift start and a great marketing opportunity. However, mMTC and uRLLC require an end-to-end 5G network which can only be achieved by deploying standalone 5G.

How does non-standalone 5G work?

The non-standalone version of 5G New Radio (NR), NSA, uses the 4G LTE network for some functionalities within the overall 5G service. In the NSA model, the end-user side of the service where higher data is required utilises the 5G radio network capabilities. However, the control functions such as signalling still use the existing 4G LTE core network- EPC. This requires installing 5G NR base stations on the radio network side and utilising 4G Evolved Packet Core (EPC) with 5G specific updates for both 4G and 5G core network functions. It means that the radio network works in such a way that the user-level functions, e.g. mobile data, QoS etc. utilise the 5G radio network node gNodeB (gNB), and the 4G radio base station, eNodeB (eNB), manages the control functions for 5G through a concept called dual-connectivity.

High-level diagram of a deployment mode or model for non-standalone 5G - NSA
High-level diagram of a deployment mode for non-standalone 5G – NSA

NSA can be seen as an early version of the full 5G NR network that presents a mobile-broadband focused 5G deployment option to the mobile operators. The average 5G data speeds are considerably higher than the average 4G speeds and good enough for streaming 4k and even 8k videos. The improved latency in 5G NR networks also makes augmented reality (AR) and virtual reality (VR) use cases possible. The other more futuristic use cases of 5G need ultra-high reliability and ultra-low latencies, which are not possible through 5G NSA. Have a look at our dedicated post on average 5G mobile broadband speeds.

What is standalone 5G?

The standalone 5G is an independent 5G network deployment model that allows mobile operators to launch a full end-to-end 5G New Radio-NR network. The standalone model, SA, can deliver the futuristic use cases of 5G that require more than just high-speed data. Standalone 5G can support higher frequency bands to deliver ultra-low latency. It can also support lower frequency bands, e.g. 600 MHz and 700 MHz, to connect billions of low-powered devices. Standalone 5G enables massive machine type communication (mMTC) and ultra-reliable low latency communication (uRLLC) use cases, including self-driving cars, smart cities, and many other B2B use cases in the manufacturing industry.

Is standalone 5G better?

From a capability perspective, standalone 5G can allow operators to do a lot more than high-speed mobile broadband. However, standalone and non-standalone deployment models are not so much about which one is better but more about what a mobile operator wants to achieve with 5G. An operator’s choice will need to align with their business strategy regarding who their key customer segments are and what services the operator wants to offer them. The consumer segment is usually a big one for any mobile operator, so enhanced broadband through non-stand-alone (NSA) is a great opportunity and a quick win to achieve 5G penetration. On the other hand, standalone 5G can give an operator the required muscle power for the large enterprise customer segment. Depending on the operator, at least for now, NSA may be more of a consumer-focused option, whereas SA may be better placed to serve enterprise-level use cases. You may check out our dedicated post to learn what B2B vs B2C customer segments mean to a mobile operator.

How Does Standalone 5G Work?

In standalone 5G NR, SA, both mobile network functions, including the control plane and the user plane, are 5G specific. From an architectural perspective, the 5G NR base stations form part of a radio network that works alongside a cloud-native 5G Core network. When a cloud-native 5G core network is employed, the connectivity for 5G devices is enabled by the 5G radio base station (gNodeB – gNB) for both user and control planes. 4G user devices can also utilise the capabilities of the 5G core network in the standalone model. So, if any 4G devices require access to the LTE network through the 5G Core, instead of communicating with the regular 4G base stations (eNodeB), they communicate with next-generation 4G base stations (ng-eNodeB). Have a look at our dedicated post on 3G, 4G and 5G base stations to learn more about ng-eNodeB, eNodeB and gNodeB.

High-level diagram of a Standalone 5G NR deployment - mode SA, without an existing 4G LTE network
High-level diagram of a Standalone 5G NR deployment mode – SA, without an existing 4G LTE network

Standalone 5G NR makes use of the mid and high range frequency bands to enable advanced use cases that require ultra-low latency. It allows mobile operators to do a lot more than just offering high-speed internet services. With standalone 5GNR, mobile operators can support use cases like Ultra-Reliable Low Latency Communications (URLLC) and Massive Machine Type Communications (mMTC). These use cases can help digitise market verticals such as the manufacturing industry. Network slicing is another key feature that works with the standalone variant of 5G. It allows mobile operators to create virtual sub-networks for specific (business) customers. Have a look at this post to learn about the frequency bands that 5G networks use.

What is the difference between standalone and non-standalone 5G?

Non-standalone (NSA) and standalone (SA) are two different modes for the deployment of 5G New Radio (NR) mobile networks. The non-standalone 5G model is a deployment model that utilises the existing 4G LTE core network, Evolved Packet Core (EPC), for enabling 5G. Standalone 5G is an end-to-end 5G network with a 5G radio network (5G New Radio-NR) and a 5G Cloud-Native Core Network (5GCN). NSA can work for an operator as an interim step towards SA. When 5G networks reach a higher level of maturity over the next few years, we will likely see an acceleration in standalone 5G network deployments.

Here are some helpful downloads

Thank you for reading this post, I hope it helped you in developing a better understanding of cellular networks. But sometimes, we need some extra support especially when preparing for a new job, or studying a new topic, or maybe just buying a new phone. Whatever you are trying to do, here are some downloads that can help you:

Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy which explains the network nodes e.g. BTS, MSC, GGSN etc.

Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and challenges given how quickly the industry evolves. The bigger picture comes from experience which is why I’ve carefully put together a few slides to get you started in no time. So if work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on product overview and product roadmap.

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