Small Cells, DAS Evolve to Meet Changing Connectivity Needs

Wireless operators are experiencing continued rapid growth in mobile broadband traffic, driven by unlimited data plans and the growing ecosystem of Internet of Things (IoT), smart-city and automotive applications. According to a report from telecom equipment manufacturer Ericsson, smartphone usage in North America reached 8.6 Gigabytes (GB) per month per smartphone by the end of 2018. That number is set to reach 50 GB per month by the end of 2024.

On top of that, wireless networks are expected to support about 29 billion devices by 2022, many of which will be installed or used indoors. As wireless operators race to keep up with exploding demand for mobile voice and data connectivity, in-building wireless solutions are assuming an increasingly important role within the broader network.

Two of the most prevalent in-building technologies — Distributed Antenna Systems (DAS) and small cells — have provided a way for operators to supplement coverage and capacity for indoor spaces not adequately served by the outdoor macro network, and relieve pressure and congestion from outdoor data demands. Cellular telephony originally was conceived as a mobile technology with a focus on outdoor usage, with base stations and antenna equipment designed to operate at high power over long distances. Now, the intrinsic benefits of mobility and the advent of smartphones have combined to make mobile phones the preferred medium for indoor communications as well.

The Wireless Infrastructure Association’s (WIA) HetNet Forum released a new report, “DAS and Small Cells Evolve to Meet Today’s and Tomorrow’s Connectivity Needs,” detailing the current state of two leading in-building technologies – small cells and distributed antenna systems (DAS) – to address the demand for mobile voice and data connectivity. HetNet Forum members Advanced RF Technologies, Boingo, CommScope and ZenFi Networks produced this report to focus on how DAS and small cells are deployed today, the role of spectrum in future deployments, and what 5G technology means for DAS and other small cells.

It’s held that up to 80 percent of cellular traffic occurs indoors, where the network may have more difficulty reaching, depending on the nature of the building and the position of nearby wireless infrastructure. With the continued proliferation of wireless devices and mobile applications, plus new ones falling under the broader IoT label, and the evolution to 5G, the amount of traffic that originates indoors is positioned to explode, both as a percentage of overall traffic and in absolute terms.

The macro network has been and continues to be effective in reaching inside buildings in most cases. But outside-in approaches can be hindered by the advent of energy-efficient building practices, such as Low-emission (Low-E) glass, which has been shown to reduce radio signal strength by as much as 15 decibel-milliwatt (dBm). This means that the signal is only 1/32 its original strength after it passes through the glass — roughly equivalent to passing through a 1-inch-thick sheet of concrete. DAS and small cells are two technologies that can supplement the macro network with indoor coverage and capacity that may be delivered directly within a building or venue. Deployed outdoors, DAS and small cells also have the same effect of bringing the network closer to the end user.

“Heterogeneous networks that incorporate macro cells, small cells, distributed antenna systems, and fiber are on in-building systems essential to the successful deployment of 5G networks,” said Executive Director of Member Services at WIA Tracy Ford. “In the six years since the HetNet Forum originally addressed the role of small cells and DAS in wireless networks, technology has evolved, and new spectrum opportunities have emerged that have changed how these products are deployed. This updated paper, written by HetNet Forum members who work with these technologies every day, is a must read for anyone involved with building next-generation wireless networks and delivering ubiquitous connectivity.”

The report can be downloaded here: