Small cells bring IoT in from the cold
Strange behavior has been reported across Scandinavia. People in accommodations built to meet new environmental standards are going outside onto cold balconies to use their mobile devices. Why?
Media stories report unreliable mobile signals inside homes because of highly insulating building materials and windows. While these minimize energy consumption, they also weaken radio signals from nearby base stations. In these regions, many households no longer have a fixed line, meaning people are forced to go outside in even the coldest weather just to stay in touch.
Indoor coverage, not just in homes and not just in Scandinavia (new building standards are being rolled out across the world), is a growing issue for us consumers and will become a major challenge for operators as the Internet of Things (IoT) aims to connect a huge number of devices inside all kinds of buildings. After all, you can’t take IoT-enabled smoke alarms or building management controls outside onto a balcony to connect them.
We’ve been doing some testing on highly-efficient triple-gazed windows with metal coating. It turns out that signals are reduced by up to 30dbm, which in radio terms is about 1,000x signal attenuation. Our testing showed that even in buildings with an LTE macro base station pointing directly at it (a rare occurrence), subscribers’ mobiles would struggle to get a decent uplink speed.
While the more penetrating Narrow Band IoT (NB-IoT) or LTE-M technologies can reach much further, our tests show the 15-25dbm typical coverage gain is just about cancelled out by new window glazing, which not only traps heat, but radio waves too.
To compound the issue, in most cities, outdoor macro base stations are often on rooftops with their antennas pointing down towards the street. This means they provide indoor coverage only between about the tenth floor down to the first underground floor. Other Nokia tests have shown that coverage will depend on the building structure, for example, NB-IoT and LTE-M may reach no more than two or three floors further down and only up to the 15-20th floor. This would mean poor IoT connectivity for underground car parks, tube stations, deep basements and all high floors.
First IoT upgradeable small cells
Fortunately, many operators are deploying more indoor small cells. For these operators, starting in 2017, all Nokia LTE Flexi Zone small cells (existing and new) can be upgraded by software to also support 3GPP NB-IoT and LTE-M technologies. The upgrade is an industry first. It means that in buildings with Flexi Zone, operators will have an easy and cost-effective way to solve most IoT indoor coverage problems.
As well as supporting existing small cell networks inside large enterprise buildings, shopping malls, hotels, airports and other public venues, Flexi Zone now gives operators a rapid, low cost way to win new IoT business not previously practical in many places. IoT-ready small cells are the most cost-effective way to reliably cover sprawling industrial, mining and drilling sites in remote locations without macro network coverage. Maybe even the odd remote castle turned luxury hotel, with 1 meter thick heavy stone walls could benefit from small cell-based IoT.
Furthermore, although Nokia macro base stations can also be upgraded to IoT, many others cannot. High power Flexi Zone small cells such as the Flexi Zone Mini-Macro can be deployed on these sites to create an underlay network that provides the same IoT coverage as a macro, but at minimal cost.
Finally, in very large buildings, operators have traditionally used Distributed Antenna Systems (DAS) powered by a Macro base station. Yet most of these DASs are still only 2G/3G as the LTE upgrade is very costly. In these legacy DAS locations, small cells can be a very cost-effective way to upgrade or complement DAS and bring LTE for both subscribers and IoT devices.
As IoT comes in from the cold, Flexi Zone small cells that can now support LTE for humans and machines, will help operators prepare for the hot new business opportunities ahead.
Find out more about how Nokia small cells help operators around the world to deliver cost-effective capacity and coverage, indoors and outdoors.
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