5G – Gee Whiz or G-Force?

James Crawshaw

I've lived through a few mobile generations in my time and on the surface 5G seems to be shaping up, much like the others, to be evolutionary not revolutionary. The initial "non-standalone" implementations of 5G will, after all, use a 4G core and the radio access network of 5G will blend the New Radio air-interface with legacy cellular technologies as well as other wireless standards such as WiFi. However, the more I dig into it, it seems 5G might actually be more of a catalyst for change for the industry, a new way of designing, deploying and operating communication networks.

The story so far
The transition from 1G to 2G mobile was about moving from analog to digital, the use of some new frequency bands and the replacement of frequency division multiplexing with time division or code division multiplexing (CDMA). 2.5G introduced packet switching, while 3G saw new frequency bands and a convergence of global standards around CDMA. When 3G failed to live up to the hype I lost faith in the revolutionary impact of mobile Gs. But the industry quietly got on with improving things with the rollout of HSPA (3.5G). The advent of LTE (4G) saw further advances with the move to orthogonal frequency division multiplexing, multiple input multiple output (MIMO), and an all-IP network. Then LTE-Advanced introduced new concepts such as carrier aggregation (combining channels from different spectrum bands), and heterogeneous networking (mixing small and big cells).

5G builds on aspects of LTE-A such as MIMO (it's massive now though) and adds new features such as beamforming (focusing radio signals towards specific users). These enable 5G to use new, high-frequency spectrum bands that were unsuitable for prior generations. 5G New Radio also introduces innovative technologies such as scalable numerology to support diverse spectrum deployments (from 1 to 90GHz), and a flexible slot-based frame structure to reduce latency.

Virtualization – a new hope
5G also builds on LTE's adoption of virtualization (mainly limited to systems such as Evolved Packet Core and IP Multimedia Subsystem) but extends it into the RAN. Thanks to virtualization, 5G networks will be able to offer dedicated capacity for specific customers or service types under a concept known as network slicing. Each slice is an independent, virtualized version of the network with unique performance characteristics.

Extending NFV to the RAN can significantly reduce RAN operational costs according to a study by Amdocs. These savings arise from the centralization of baseband units, which represents about 60% of basestation costs, according to the same study. Migrating from cloud RAN to full vRAN architecture will bring greater flexibility and efficiency, with frequencies allocated to users instead of being tied to specific locations. As IoT markets grow, vRAN will support the customization, scalability and reliability needs of a wide range of use cases. In addition, having a clearer separation between radio resource units (RRUs) and baseband units (BBUs) will open the door for open platforms and interfaces supporting multivendor remote radio units, leading to better quality and lower prices than today's proprietary stacks.

Service-based architecture – an agility enabler
One of the key architectural differences between 5G and prior generations is the concept of service-based architecture (SBA). Traditional core networks have used a point-to-point architecture to manage functions such as session management and authentication. With P2P, different network functions are connected over standardized interfaces that allow for multivendor networks. However, all these interfaces have interdependencies which make it difficult to change the network.

While that was adequate in an age of voice and generic mobile broadband, 5G is meant to enable a diverse range of services designed to meet fast-changing industry demands. The solution with SBA is to decouple the end-user service from the underlying network and platform infrastructure. SBA incorporates principles such as modularity, reusability and self-containment of network functions, enabling deployments to take advantage of virtualization, offering greater agility. SBA uses the cloud model with different functions composed into an end-to-end service using standard APIs. This makes it easier for the operator to add, remove or modify the network. SBA also facilitates network slicing by allowing reuse of network function services across slices.

OSS/BSS modernization to capitalize on 5G opportunity
In a sense, 5G dematerializes the network, adopting the best of the IT and Internet technologies and adapting them to the mobile communications network needs. The network becomes software-defined, instantiated and chained together on a just-in-time basis to deliver services. The associated compute resource, similarly to the spectrum resource, must be managed carefully by the operator to ensure services can be delivered profitably.

With network slicing 5G will allow CSPs to monetize the network beyond basic connectivity. Because the network is moving from a static to a dynamic structure, IoT and enterprise customers will be able to build their own network and manage it through a self-service portal. The agility of a 5G network based on virtualized infrastructure (from core to RAN) will enable fully automated business processes, allowing new ways of consuming digital services. To take full advantage of this will require modernization of OSS and BSS systems in addition to the mobile network itself. 5G may well represent a revolution but there will be plenty of evolution of adjacent IT systems required to take full advantage of it.

This blog is sponsored by Amdocs.

— James Crawshaw, Senior Analyst, Heavy Reading

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