Given the ever-increasing demand for indoor voice and data connectivity, service providers are looking for strategies that will help them meet short-term mobile broadband requirements as well as address the future demand for capacity. In such a scenario, small cells can help operators boost traffic performance in dense indoor hotspots through digitalisation and integration with outdoor networks. Further, small cells will be central in driving the deployment of cloud-based radio access network (RAN) architecture towards 5G deployments.
Indoor digitalisation
It took the networks some 20 years to evolve from 1G to 2G, 10 years from 2G to 3G, and just five years from 3G to 4G. Data speeds have evolved from tens of kbps to several Mbps and to hundreds of Mbps. Meanwhile, the commercial application of some 5G technologies has caused a speed leap from megabits to gigabits. As a traditional indoor coverage solution, the distributed antenna system (DAS) is unable to support these new requirements due to its analog radio frequency architecture. In such a scenario, digital small cells are emerging as the new linchpin technology for building a fully connected indoor world. With end-to-end digital architecture, high capacity, high yield, fast deployment and a scalable network architecture, small cells are being used to provide connectivity in all indoor scenarios, particularly in ultra-dense areas such as sports stadiums, urban avenues, shopping malls and big transport hubs.
Further, digital solutions support flexible cell splitting and remote software configuration. In contrast, for DAS, capacity expansion requires additional remote radio unit hardware and physical reconstruction, which is often difficult to accomplish owing to complex coordination with property owners and the high costs. Also, traditional DAS neither supports fault and service monitoring on all nodes nor full-system operations and maintenance (O&M) with visual operations. On the other hand, digital O&M can precisely monitor each node to enable O&M and visualisation across the entire indoor system. Over the course of operations, upon experiencing a device fault, indoor digital networks can perform self-optimisation in line with surrounding network conditions to mitigate any negative user experience. At the same time, automated fault diagnosis and self-fault recovery are supported to reduce manual intervention and reduce O&M costs significantly. While indoor digitalisation clearly scores over the traditional method, upgradation of the analog network ecosystem cannot be achieved overnight. It will require concerted efforts and impetus from multiple industry players to break the chain of traditional analog networks to achieve new business success.
Integrated small cell deployments
The majority of small cells are deployed in areas where macro network coverage is already present. For instance, outdoor micro cells are often used as capacity boosters in areas with good macro coverage and indoor small cells are deployed in buildings with substantial outside-in coverage from macro cells. Even small cells deployed in modern buildings with metal-coated windows and good isolation from the macro coverage must interact with the macro network as people move in and out of the buildings. Therefore, small cells must generally be deployed and operated as an integrated part of the 3G or LTE network.
When building an integrated network, small cells must deliver a good and consistent user experience. Further, small cells should not be independent of the macro network, allowing for the optimisation of concurrent systems. Also, the planning of small cell deployments should be detailed and must consider both how macro cells handle traffic as well as how they generate radio interference.
Building unlicensed spectrum
The demand for mobility continues to grow, but wireless spectrum is a finite resource. Delivery of higher data speeds and more mobile broadband capacity requires better utilisation of existing and new spectrum. Applying licensed and unlicensed spectral convergence solutions to small cells is good for network planning and helps maximise unlicensed spectral utilisation.
Cloud-based small cell architecture
Mobile networks are evolving quickly in terms of coverage and capacity, with continuous demand for additional features relating to latency, traffic volumes and data rates. By introducing cloud-based RAN architecture, operators can meet these accelerating demands using network function virtualisation techniques and data centre processing capabilities in their networks, which allow for resource pooling, scalability, layer interworking and spectral efficiency. Cloud-based RAN deployments are well suited for heterogeneous network deployments, with a mix of larger and small cells, and offer centralised functionality for radio and backhaul coordination. Indoor small cell deployments can be undertaken as small per-building cloud RANs.
Conclusion
As the availability and reach of mobile services expand to every corner of the world and delivering ubiquitous 24×7 services becomes crucial, operators will explore new business models for reaching out to their customer base. Further, with over 80 per cent of the data traffic expected to be generated indoors, small cells will be a core part of operator network strategies.
Based on the white paper, “Small Cell Network”, by the Global Mobile Suppliers Association
