5G NSA vs. SA: How do the deployment modes differ?

Non-standalone 5G

When it comes to NSA 5G, the clue is in the name: It's 5G that can't stand on its own in terms of infrastructure. NSA is a 5G radio access network (RAN) that operates on a legacy 4G LTE core -- known as Evolved Packet Core (EPC) -- and manages control plane functions. NSA includes both a 4G and 5G base station, but the 4G base station takes precedence. Because the NR control plane anchors to EPC, radio frequency signals forward to the primary 4G base station.

NSA 5G, also known as Release 15 by 3GPP, is considered the first stage of 5G. Initial 5G deployments used NSA because MNOs could use their current infrastructure to build a 5G network. Carriers with 4G LTE networks could implement a 5G RAN on top of their existing architectures. NSA 5G can serve as a steppingstone for carriers unprepared to make a hefty investment when they transition from legacy 4G LTE to 5G networks.

The drawback of NSA 5G, however, is it can't deliver certain capabilities that a pure, unfettered SA 5G network can. For example, NSA doesn't enable the low latency that is one of the biggest draws to 5G. Another disadvantage of NSA is it requires a higher level of energy to power 5G networks with 4G infrastructure. 5G NR is more energy-efficient than LTE, IEEE reported, but using two different forms of cellular technology massively increases power consumption in a network.

NSA 5G also shouldn't be mistaken for dynamic spectrum sharing (DSS), another method of deploying 5G with 4G technology. While NSA creates a 5G network with 4G infrastructure using dual connectivity, DSS permits 4G LTE and 5G NR to coexist in the same frequency band. 5G networks have a variety of spectrum bands available for use, and DSS distributes spectrum between bands based on user demands.

Benefits of NSA 5G

• Reduced costs. MNOs can build out a 5G network on top of their existing 4G infrastructure instead of investing in a new, costly 5G core.
• Easy deployment. NSA networks use 4G infrastructure with which MNOs are already familiar, simplifying both the configuration and update processes.
• Fast rollout. MNOs can release an operational 5G network quicker with NSA by using current 4G infrastructure.
• Pathway to SA 5G. MNOs configured NSA 5G networks as a foundation while SA networks developed. As SA networks roll out, carriers can replace outdated 4G network elements with 5G infrastructure to manage their existing 5G networks.

Standalone 5G

SA 5G networks include both a 5G RAN and a cloud-native 5G core, something NSA networks lack and substitute with a 4G core. Because SA networks have 5G cores, they can perform essential 5G functions and offer advantages like reduced latency, improved network performance and the ability to control network management functions with a central controller.

SA requires MNOs to configure a completely new architecture and learn how to manage it. As carriers waited for SA technology to mature, most opted to simply reconfigure their 4G networks to support 5G, as it was cheaper and more convenient.

New providers without established 4G core networks couldn't follow that strategy, though. Because they couldn't rely on a 4G core, they needed to build their 5G infrastructure from scratch. SA could soon take the crown among MNOs, as carriers start to deploy it to take advantage of the improvements it offers over NSA.

The biggest disadvantage of SA is it's costly to implement and time-consuming for network professionals to learn the new 5G core infrastructure. Regardless, it's likely that MNOs will eventually make the shift to SA because, while NSA can serve as a step toward 5G networking, it isn't considered true 5G due to its reliance on 4G LTE.

Benefits of SA 5G

• Reduced power consumption. Because SA doesn't need to operate with 4G LTE, it uses only one method of cellular connectivity and uses less power to support a network.
• More 5G use case support. Unlike NSA, SA can deliver essential 5G services, such as improved latency and increased bandwidth caps, to power ultrafast, scalable networks.

NSA vs. SA: 5G NR specifications

Ultimately, the biggest difference between NSA and SA is how each mode provides 5G. NSA uses a 5G RAN, as well as a 4G LTE core, while SA is an end-to-end 5G network with both a 5G RAN and NR core. Their methods of deployment determine how each mode supports the 3GPP-defined NR specifications.

5G NR specifications include the following:

• Enhanced mobile broadband. Functions as an extension of 4G that increases data rates to improve network speeds.
• Massive machine-type communications. Connects up to 1 million devices and facilitates quick, seamless communication between them.
• Ultrareliable, low-latency communications. Ensures network reliability by reducing latency to below 5 milliseconds.

All three features support an array of industries and services, including emerging sectors, like IoT, satellite communications and more. However, SA 5G is the only deployment mode that supports all three specifications. NSA 5G can only enable enhanced mobile broadband because it has a 4G core that can extend to support the specification. SA can enable all three features because it has a more powerful and more flexible 5G core.

Even though SA 5G is an improvement over NSA 5G, few operators have deployed the latest technology. In September 2023, Counterpoint Research reported that only 47 MNOs worldwide have released commercial SA 5G deployments.

Many MNOs previously said they were eager to develop SA 5G, but installments are behind. The global economy is in a downturn, and MNOs also find it difficult to earn ROI on 5G. Because carriers have yet to find many lucrative or killer applications that justify the transition to SA 5G, NSA currently reigns supreme.

However, research showed the advanced capabilities SA 5G offers, such as enhanced mobile broadband, fixed wireless access, network slicing and more, show revenue potential. SA 5G itself could be the killer use case that increases 5G's ROI and provides reason to support the transition to SA 5G. Despite the simplicity and inexpensive costs of deploying NSA, carriers should make the move to SA 5G to reap the most beneficial and anticipated capabilities of the technology.