As countries step into the 5G era, they are increasingly looking to explore the varied use cases of small cells to smoothen the path towards 5G implementation. Globally, policymakers and regulatory bodies in the telecom domain are looking to devise policy frameworks that ease the deployment of small cells, thus facilitating seamless service delivery thro­ugh 5G networks.

The recent edition of the Small Cell Forum’s (SCF) “Market Forecast Report” includes a comprehensive analysis and fo­re­­casts of small cell network deployments. According to the report, the applications of small cells have expanded dramatically, from being deployed merely in residential environments to powering urban densification and emerging industrial 5G use cases. The trends identified in the report justify 5G roll-outs and expansion of the business case beyond mobile bro­adband. Moreover, the study advocates that deployers should work with (or expand) 4G or Wi-Fi networks, and asserts that multi-network integration or management will be an important element of small cell platforms, even when extending to non-terrestrial networks such as low earth orbit satellites for small cell backhaul.

A look at the key findings of the report…

Deployment forecasts

The report by SCF assumes a steady gro­w­th in small cell deployment between 2020 and 2027. For this period, the report forecasts a compound annual growth rate (CAGR) of 15 per cent for the global market, which will result in the cumulative deployment of almost 36 million radios by 2027. The growth in this period is expected to be driven majorly by an uptick in the deployment of urban small cells in the form of public networks. These are typically deployed outdoors on roofs or street furniture, or indoors in public venues such as railway stations and malls. Outdoor deployment of such networks is expected to be focused on rural and remote small cells. This would account for a small percentage of the total in terms of volumes as such deployments would address coverage rather than the challenges of dense capacity. However, the focus on rural and remo­te area deployment is poised to become increasingly business-critical, as more 5G applications demand ubiquitous coverage, especially for vehicular, drone-related or internet of things-related use cases.

In addition, small cells will continue to enable the extension of mobile broadband to remote communities, driving the socio-economic benefits of high quality connectivity. In the forecast period, rural small cell deployments are predicted to grow at a CAGR of 18 per cent, to reach almost 200,000 new radios deployed in 2027. The ma­jor chunk of small cell deployments th­roughout this period is forecasted to be in enterprise, with small cells being imple­m­e­nted for private networks, or to improve the coverage and capacity of the public network within enterprise environments. Meanwhile, the increasingly business-critical nature of mobile broadband is expected to drive an increasing number of enterprises to demand high quality cellular connectivity, often to complement Wi-Fi and fibre, for more than just voice and data coverage indoors, which are the traditional enterprise use cases for small cells.

Common foundation

As stated in the report, the diversity of use cases for small cells will necessitate a common foundation to avoid fragmentation. While much of the promise of 5G lies in its ability to support a wide range of ad­v­an­ced capabilities, these are heavily associated with small cells because small cells work efficiently in dense environments, wh­ere connectivity and data can be hand­l­ed close to the end user. Moreover, as per the report, locations such as transport hu­bs, manufacturing plants, ports, stadiums, shopping malls and office buildings are destined to observe significant traction in the demand for small cells.

To this end, the challenge for small cell developers is to create products and software platforms that can adapt to any set of requirements, without the market becoming too fragmented to support scale. In order to mitigate the risks, the diversity of deployment models and use cases needs to be supported through common foundations in the form of standards, reference designs, blueprints and certification. The report has also cautioned deployers against the risks of losing economies of scale in case of fragmentation. Many stakeholders ag­ree that reference designs and bluepri­n­ts, established by an open cross-sector bo­dy, are an effective way of driving scale up and mitigating the risks of increased cost and complexity in a fragmented platform, implementing open interfaces and pre-integrating components to reduce cost and risks for vendors and deployers.

Evolving architecture

The early deployments of 5G may have been based on conventional architectures, but operators are now starting to move towards networks based on several significantly new elements. In particular, they are evaluating, and starting to deploy, two important and interrelated elements – 5G standalone (SA) with cloud-based 5G core, and virtualised radio access networks (vRAN). Both of these are significant and challenging migrations, as they deploy networks in the cloud, enabling new levels of service agility, automation and resource optimisation – but also entailing major changes in technology, skills, network op­e­rations and, potentially, suppliers.

As of the first quarter of 2022, the number of commercial roll-outs of 5G SA worldwide is more than thrice the number of networks in small cell environments. The implementation of 5G, especially in SA mode, is often a trigger for reassessment of small cell architectures. In particular, disaggregated and vRAN architectu­res are starting to gain ground. As with 5G SA, the adoption of new open radio access network (O-RAN) architectures will be faster in small cell and enterprise environments than in public and macro networks, owing to the lower number of legacy networks to migrate. The performance challenges are also somewhat more manageable for virtualised architecture. The repo­rt predicts that the deployment of O-RAN small cells will grow at a CAGR of 146 per cent in 2021-27, to reach 51 per cent of total small cells deployed at the end of that period. It also predicts a roll-out rate of 2.7 million radio units in enterprise and private environments, and 1.8 million in public networks.

Critical enablers

While open platforms, virtualisation and deployer diversity are key to accelerating the adoption of small cell networks, an ef­fective policy framework and spectrum bands are critical enablers as well. An efficient policy framework can comprise spectrum allocation, siting approvals and ac­cess, network sharing permissions, and op­en supply chains. The markets where po­licymakers and regulators adopt progressive and liberal approaches in all of these areas will be the ones where small cells make the most headway, and their benefits are delivered quickly. Though an effective policy framework is crucial, flexibility of policy in terms of accessibility is also important. Just as the architecture and primary use cases of a network influence the deployment model, so does the spectrum. A shared spectrum enables a wider variety of companies to deploy and operate cellular networks. Additionally, there is a heavier reliance on non-traditional operators in millimetre-wave bands than in mid-band spectrum, owing to their higher ca­pacity (ability to support many deployers), the prevalence of flexible licensing in high frequency bands, and the greenfield nature of the bands, which encourages new use cases with, in many cases, new business models for operators. The study infers th­at by 2027, 79 per cent of small cells dep­loyed in flexible or shared spectrum will be used for 5G, compared to 95 per ce­nt in licensed bands.

Conclusion

The period from 2022 to 2027 is poised to witness rapid change and expansion in the small cell market, driven by enablers of increased diversity in use cases, deployment business models and architectures. That said, the flexibility of open networks, shared spectrum and new operating models has the potential to drive significant growth in small cell roll-outs and in the social and economic value that networks deliver for operators, enterprises and citizens. However, this growth is reliant on several key challenges being addressed urgently. Doing so would help address the biggest risk – that of fragmentation. A common foundation on which vendors and operators can innovate in a unified and interoperable way is expected to be the biggest single factor in ensuring that the small cell industry meets, or exceeds, the predicted growth.