Small cell deployments have been gaining steam. Indian telco Reliance Jio announced in late 2015 its plans to build what it is calling the largest small cell deployment happening in the world. Global mobile operators are including small cells in their strategy to manage exploding traffic on their networks as subscriber demand for mobile video and the burgeoning Internet of Things market continues to grow. As such, three key trends for small cells are emerging – HetNets, LTE (News - Alert) in unlicensed spectrum, and the cloud RAN.

Hot on HetNets

Mobile operators are increasingly deploying a combination of macrocells, Wi-Fi, distributed antenna systems, and small cells to create mobile heterogeneous networks (or HetNets) and maximize their available spectrum. HetNets are critical to mobile operators’ strategy to build out their networks to support exploding data traffic, primarily in dense urban areas where network is seriously strained.

In a HetNet environment, mobile subscribers will experience seamless coverage as they move between base stations. Small cells with self-organizing network capabilities are critical to ensure the effective coordination of time and frequency resources and provide dynamic interference management. The Small Cell Forum is putting a focus on HetNet drivers, barriers, and business cases in Release 6.

Unlimited Potential for Unlicensed  

The most burning topic in the small cell world today is LTE in unlicensed spectrum. By aggregating unlicensed spectrum in the 5GHz band with an anchor in licensed spectrum, mobile operators can add needed capacity and coverage to their networks without the expense of new spectrum.

There are several approaches underway. In the U.S., the focus is on LTE-Unlicensed – a pre-standardized path to deployment from the LTE-U Forum. The technology is seeing traction with deployments planned for mid-2016. LTE-U is also in favor in China; China Mobile (News - Alert) recently completed field trials of a small cell solution from Baicells, and Radisys and is now shifting to deployment in the field.

The standardized path – led by 3GPP – is known as LTE-Licensed Access Assist. Based on 3GPP Release 13, LTE-LAA will include listen before talk, which ensures fair sharing of spectrum with Wi-Fi. As work on the specification is just being completed, we anticipate LTE-LAA deployments will roll out in 2017.

Both LTE-U and LTE-LAA will rely on small cells. Mobile operators will deploy small cells in unlicensed spectrum and use carrier aggregation to combine spectrum with macrocells based in licensed spectrum. This approach allows the macrocell to deliver critical information and guaranteed quality of service, while small cells operating in unlicensed spectrum can opportunistically boost data rate. In addition, the low power requirement of small cells is well suited for unlicensed spectrum. 

Clear Skies ahead for Cloud RAN

Mobile operators are also turning to virtualization technologies to alleviate strain on their networks. In a cloud RAN architecture, mobile operators deploy radios in the network and move the functionality to the cloud through the deployment of virtual base stations. This approach allows operators to take advantage of processing aggregation and the dynamic allocation of resources from a central processing unit. The result? Improved network efficiency, reduced power consumption, lower total cost of ownership, and reduced capex and opex.

Small cells will remain a critical part of the network in this new virtualized environment. The Small Cell Forum addressed this opportunity in Release 5.1 in June 2015, supporting an accelerated path to virtualized small cells. To further aid small cells in the cloud, Radisys has partnered with ASOCS (News - Alert) to deliver virtual base stations, leveraging its LTE small cell software for mobile operators’ cloud RAN deployments. We’re currently are working with our partners to bring the cloud RAN from the lab to the network.

Big Opportunities for Small Cells

HetNets, LTE in unlicensed spectrum, and the cloud RAN will all continue to rely on small cells. Pioneering mobile operators that are deploying small cells as part of their overall network strategy are well positioned to not only meet subscriber demand for bandwidth and coverage, but to delight those subscribers with a seamless user experience. At the same time, they can reduce overall network costs and improve spectrum efficiency. That’s a big win for small cells and operators alike.