5G SA: Migration paths and legacy networks. By Martin Keenan
From an industry point of view, there are currently two types of 5G network as defined by the 3GPP standards, non-standalone (NSA) and standalone (SA). Most mobile operator networks have already begun the long process of migrating to 5G, and with a desire to capture new markets as quickly as possible, will mainly be considering 5G NSA, which enables operators to utilise legacy 4G infrastructure alongside 5G as their rollout progresses. Indeed, since 2019 hundreds of operators across the globe have taken the 5G NSA route.
Migration pros and cons
However, the choice is not as stark as it might seem. Although 5G NSA allows operators to begin incrementally rolling out infrastructure and developing new business models at the same time, there are a host of applications - specifically those that require ultra-low latency and higher capacity - which will only be feasible with 5G SA. The result is that many enterprises and adopters of 5G for IIoT deployments have waited, then gone straight from 4G to standalone 5G, which offers broader use case fulfillment. In addition, having deployed SA, an operator can offer the full range of optimised 5G services immediately, creating a point of difference from NSA competitors, maximising the monetisation chances.
The key disadvantage to taking a direct route to 5G SA is the large initial investment required, and the fact that the legacy 4G/LTE network also needs to be maintained until it is entirely replaced by the new 5G network.
There are a variety of pros to the 5G NSA route as well, especially for providers targeting business users and consumers with high-speed connectivity. Being first in a new market is always helpful from a business perspective, and this also maximises the use of the existing installed LTE base. That LTE base is vital from a technological perspective too, as it means mobility management is possible with minimal impact - only peak data rates will be affected. However, the use of new 5G spectrum enables operators to boost capacity and increase efficiency, as well as begin to explore new business models and use cases on a trial basis.
5G SA benefits gaining traction
That said, 5G SA offers a smorgasbord of powerful and brand new features that will increasingly drive enterprises and operators to move on up from NSA. Arguably one of the most powerful of these features is network slicing, which enables a 5G SA network operator to create multiple end-to-end virtual networks within their existing network. This was possible in a very basic form in LTE networks, but 5G SA enables the creation of virtual data pipelines as well as full control and management functions for each type of service, enabling highly granular controls of the new virtual networks.
This ability to guarantee the quality of data transmission at a network level allows a huge range of new business models and revenue streams to be created. For example, connected cars and/or city infrastructure could have dedicated capacity, as could the emergency services. For enterprise deployments too, this feature will be vital, allowing the same 5G SA network to deliver a plethora of services, from general office connectivity to factory IIoT automation, but without compromising on the performance and reliability of any segment.
Although Massive MIMO (mMIMO) has been part of 5G since the beginning, an essential element in ensuring the quality, throughput, and capacity of the radio link (alongside beamforming), the scope of the technology is improving with each 5G release, enabling vastly improved rata rates. One estimate saw Release 16 devices improve on Release 15 by 50%, and date rates to nearly double by Release 18 - an interesting conundrum for data-intensive application rollouts.
Ultra low latency (URLLC) is another benefit of 5G SA that really stands out, allowing a network to be optimised for processing large amounts of data with extremely low latency and
high reliability. URLLC uses mini-slot scheduling and UL grant free transmission to achieve low latency requirements, making it particularly useful for essential services and very latency sensitive services such as remote factory robot management and C-VX2 applications.
5G SA still early days
It is still early days for 5G SA, but adoption is surging. The rise of private 5G networks indicates the substantial amount of interest from enterprise as a whole, enabling businesses to pick and choose their own bespoke network rather than wait for operators to offer it.
Ericsson is one of the latest manufacturers to offer a private 5G network service, launching Ericsson Private 5G in June 2021. It offers a blend of 4G LTE and 5G SA, and primarily is targeting a broad set of verticals including manufacturing, mining and process industry, offshore and power utilities, as well as ports and airports.
Elsewhere, OPPO has collaborated with Thales to announce the world’s first 5G SA-Compatible eSIM in the company’s latest flagship smartphone. The beginning of market availability of eSIM technology - baked directly into the device, rather than the existing physical SIM card - in combination with 5G SA will have considerable ramifications for operators, enabling a far more granular level of connectivity plan negotiation and on-the-fly selection. That is likely to appeal to end users, but also has clear implications for IIoT and automated vehicle connectivity too.
Overall, the paths to SA may vary according to market requirements, but the roads all lead the same direction. Full-fat 5G SA architecture offers considerable benefits for all links of the value chain, and by fixing a migration path from LTE with minimal delay all market players can begin to explore them.
Martin Keenan is the Director of Technical Development at Avnet Abacus