Small cell deployment began with 3G, was ramped up with 4G, and is now poised for significant growth with 5G. Small cells are an essential component of telcos’ 5G roll-out strategies. 5G deployment requires radio equipment to be closer to the consumer than it is in 3G or 4G networks, which makes small cells a natural fit for 5G roll-out. At present, telcos are focusing on deploying small cells in low frequency bands for delivering improved bandwidth to customers. However, post-2021, the small cell network is expected to expand on the back of IoT and M2M technologies.

A look at the role of small cell deployments in the 5G era, key technology considerations for 5G that will impact small cell deployment, implementation challenges and the way forward…

Role of small cells in 5G

Each small cell has a coverage area, typically less than 100 metres. Small cells are an ideal solution for meeting the growing data demands in densely populated areas as they work seamlessly with towers to increase capacity. The deployment of small cells enables network densification, particularly in urban areas, and enhances network capacity without additional spectrum. Small cells provide telecom connectivity in weak network connectivity areas, typically enclosed premises such as residential buildings, offices, shopping malls, restaurants, hotels, hospitals, airports and railway stations.

In addition to network densification benefits, small cell deployment also offers cost savings to telcos. The cost of deploying new sites is clearly a key issue for network operators. The cost of fibre and power distribution is a primary cost driver in these networks. Thus, deploying small cells as an alternative to traditional trenching provides huge savings in the network cost. As per industry analysts, small cells offer savings of about 40 per cent on site rentals, energy costs, etc. As per industry experts, as the continuing increase in data traffic is driving the need for network capacity expansion, additional radio sites are needed, and small cells provide a cost-effective solution.

Key technology considerations of 5G

Role of SDN/NFV in 5G deployments

A key unique feature of 5G is network programmability. In the 5G era, several new communication demands will emerge from a range of devices, users and companies. To sufficiently manage these demands, 5G networks will have to be programmable, flexible, modular and software-driven to support a diverse range of services. Software-defined networking (SDN) will play a key role in this regard by enabling network programming. A programmable 5G network provides service agility by reducing the time for service creation and adaptation; service diversity with a single infrastructure for multiple services; and resource efficiency by allocating the right number of resources wherever needed.

Another disruptive concept that will emerge in the 5G era is network slicing. Through network slicing, a single 5G

physical network can be sliced into multiple isolated logical networks of varying sizes and structures, dedicated to different types of services. It will allow operators to create different levels of services for different enterprise verticals, enabling them to customise their operations. To leverage these benefits, operators will have to adopt network function virtualisation (NFV) solutions, which provide the necessary infrastructure for the orchestration and automation of network slices. Each of these network slices will have its own characteristics in terms of speed, latency and quality of service.

Role of mmWave in 5G deployments

5G expansion will be undertaken by deploying radio in new bands such as the sub-6 GHz range, mmWave frequency bands and existing LTE bands. Software enhancements can help rapidly upgrade existing LTE bands to support 5G services. mmWave holds tremendous potential in terms of speed, capacity and latency.

Small cells are critical for deploying 5G networks in mmWave bands. This is because mmWave cannot be deployed via a macro network owing to its propagation characteristics, which restrict its ability to travel far, and penetrate structures and obstacles. Small cells help fully leverage mmWave deployments.

Fixed wireless access to increase once 5G kicks in

Currently, almost half the households lack access to a fixed broadband connection. This is set to change given the speed and capacity of advanced 4G technologies and their subsequent evolution to 5G. The provision of broadband services to homes and small- and medium-sized enterprises using fixed wireless access (FWA) has emerged as an economically viable opportunity.

Given the high density of households in India and the growing availability and uptake of fixed broadband alternatives, FWA has immense scope in India. Small cells can be leveraged for network densification to enhance FWA.

Role of open RAN in 5G deployments

A key factor driving the adoption of open RAN is its role in facilitating 5G networks. According to industry reports, 5G deployment costs are expected to fall by 30 per cent between 2019 and 2022 if a network is built in the traditional way, and by 50 per cent if it is based on an open architecture. Open RAN enables operators to increase the number of their network infrastructure partners, and deliver better and more cost-effective 5G networks.

Recently, Airtel and Qualcomm Technologies announced their collaboration for accelerating the deployment of open RAN-based 5G networks in India. Airtel will utilise Qualcomm’s 5G RAN platforms to roll out virtualised and open RAN-based 5G networks.

Role of massive MIMO in 5G deployments

Massive multiple-input multiple-output (MIMO) technology has been playing a vital role in enabling the shift to 5G. It is helping telcos build a 5G-ready transport network that offers increased capacity and coverage without investment in additional spectrum.

In India, Vodafone Idea (Vi) has deployed more than 12,000 massive MIMO sites across Mumbai, Delhi-NCR, Ahmedabad, Pune, Hyderabad, Madhya Pradesh and Chhattisgarh. Bharti Airtel, too, has deployed more than 100 hops of enhanced MIMO microwave links, based on the latest MIMO technology developed by Huawei. Meanwhile, Reliance Jio is deploying massive MIMO technology in some of the metro cities that are seeing huge traffic growth.

Issues and challenges

While rapid and widespread small cell deployment is the next step for the industry, the journey is laden with challenges. For instance, in some countries, regulations and policies have imposed excessive administrative and financial obligations on operators, thus blocking investments and slowing down small cell deployment. Further, prolonged processes for seeking approvals result in delays. In many countries, the time taken by the local authorities to approve planning applications for small cell implementation can stretch to 18-24 months.

Another challenge is lengthy procurement processes to obtain exclusive rights to the deployment of small cell equipment, which can increase costs and lead to time delays. High fees and charges demanded by local authorities for allowing access to street furniture are also hampering small cell deployments across the globe. Meanwhile, telecom operators in some countries may not have the right to install small cell apparatus on street furniture such as lamp posts due to local rules and regulations prohibiting it.

Apart from this, there are some backhaul development challenges that impact operators’ ability to deploy small cells.

Typical outdoor small cell sites are 3-6 metres above the street level and require more cost-effective, scalable and easy-to-install backhaul solutions that can support a uniform user experience across RAN. There is, however, no one-size-fits-all solution for small cell backhaul and a trade-off among capacity, coverage and cost has to be made.

Global deployment experience and the way forward

According to the Small Cell Forum, small cell deployment and 5G roll-outs are dominated by China and North America at present. By 2026, China and Southeast Asia will account for 36 per cent of the cumulative installed base, and North America for 19 per cent, while Europe and South Asia (led by India) will account for about 15 per cent each.