February 2018 1

THE BEST-LAID PLANS OF 5G

February 2018 1

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THE BEST-LAID PLANS OF 5GPity the radio frequency (RF) engineer trying to grapple with inaccurate geodata. No matter how swanky the propagation software package, if it’s being fed with low-resolution and high-error map data then any sharp-looking coverage model projected on-screen — showing signal interactions with terrain, trees, buildings and other so called ‘clutter’ data — it is likely to be a poor match for the real world.

The result? RF engineers tasked with planning optimal deployment of the latest mobile network technologies will be running computer-simulated

radio propagation models that simply don’t work in the field. This will invariably lead to higher hardware costs, along with time-consuming and expensive field visits by network engineers to try and fix the problem. In the meantime, the mobile network operator (MNO) is left hamstrung by slower time-to-market and the prospect of customers complaining about poor signal coverage.

Worryingly for MNOs, many RF engineers think they’re either working in the dark or pretty much close to it. According to a recent survey of RF experts from around the world, only one in five

share:

WITHOUT ACCURATE GEODATA, ANY PLANS FOR COST-EFFICIENT ROLLOUT OF 5G NETWORKS ARE LIKELY TO GO AWRY. SAY HELLO TO HIGHER HARDWARE COSTS AND POORER SIGNAL COVERAGE. THE GOOD NEWS IS THAT SOMETHING CAN BE DONE ABOUT IT.

Geodata for telecommunication planning involves multiple mapping data layers that not only help predict signal propagation but help identify data traffic patterns.

3D vectors

Populationdensity map

2D linear vectors

Clutter data

Terrain

Ortho imagery

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THE BEST-LAID PLANS OF 5G

could say they were “highly confident” about geodata accuracy1. The rest, to varying degrees, were unconvinced. By contrast, nine out of ten said geodata was either “important” or “crucial” in mobile network design. There seems a mismatch between what RF engineers need and what they are getting.

MORE OBSTRUCTIONS AROUND THE 5G CORNERIf nothing is done, the problem looks set to get worse. As many MNOs enter the planning phase for 5G network rollout, the need for an accurate representation of obstructions that might block or weaken radio signals becomes all the greater.

By using higher frequencies, 5G networks will be much more susceptible to signal attenuation than technologies using low-band airwaves. While long-range 4G signals can bend around buildings and other obstructions, higher 5G frequencies don’t have the same flexibility. They can’t travel over long distances and are likely to be impeded by any obstruction that happens to be in their way.

1 Commissioned by DigitalGlobe, the global survey was conducted in late-2017. The number of RF engineers canvassed was 65.

Andy Baffes, Vice President and co-founder of EGS Technologies, a geodata consultancy, thinks 5G will focus minds in RF planning departments. “Direct line-of-sight is a critical issue with higher frequencies,” he says. “5G rollout and implementation are clearly helped if the true environment can be modelled more accurately.”

WHAT DO RF ENGINEERS NEED?RF engineers recognize the value of good geodata–not only to provide realistic simulations of their networks, but also to improve customer experience. No surprise, then, that the majority of survey respondents placed high importance on ‘true-to-life’ 3D GIS (geographic information system) data when it came to simulating models for next-generation network deployment.

Another requirement highlighted by nearly 40% of RF engineers canvassed was that resolution for 3D modelling should be 1m or better. In other words, the image of the Earth’s surface, typically captured by satellite for large-scale GIS data gathering, is magnified and split into squares measuring no more than 1m on each side. The smaller the square, the higher the resolution. And the higher the resolution,

Clutter classifications are created using spectral analysis tools run on satellite image data as well as elevation and feature analytics combined with third-party map data.

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the more features are revealed that might impact radio propagation, such as trees, terrain, vegetation, and buildings.

High-resolution is not entirely the same as high accuracy, but there is a close correlation. By being able to identify features more clearly, it becomes possible to measure their height with greater accuracy. Survey respondents, for the most part, want clutter height data to be within 2m or less. This level of accuracy, combined with 3D vector building data — which allows buildings to be drawn in much sharper detail — is increasingly required for sophisticated digital mapping. And not just in densely-populated areas downtown. Baffes points out that more and more MNOs are requesting vector building data for commercial business districts, office parks and residential suburban areas. It’s an emerging trend borne out in the RF engineer survey2.

The beauty of detailed vectorization of feature data is greater granularity. It becomes possible to identify various undulations in a building, for example, such as different stories jutting out at different angles from one another. Buildings are rarely monolithic structures. Roof furniture, in the shape of air-conditioning units and elevator towers, can also be displayed more accurately in 3D modelling. Accuracy of this sort is crucial for the more advanced radio propagation models needed for 5G.

Likewise, geodata must be up-to-date. “Because of fast-changing urban environments, the question of data currency is going to become much more important,” says Baffes. Survey respondents agreed. Data currency was flagged overall as the most important criterion for selecting geodata, followed closely by high resolution and detailed graphics for buildings.

A common feature of geodata procurement today, observes Baffes, is the finger-drumming wait after the order is placed. It can take weeks or even months. When it does become available, the geodata is then

2 When asked what type of geodata they expected to need for deploying next-generation networks in suburban markets, 45% of survey respondents answered ‘2m or better clutter height data plus 3D vector building data’.

NAVIGATING GEODATA Geodata, as its name suggests, refers to information about geograph ical features. Then there’s ‘clutter data’, which typically refers to land use. A clutter map, for example, will identify urban versus residential land and include the likes of terrain, trees, vegetation, and buildings. Of interest to RF engineers is height accuracy of clutter data and resolution levels. The higher the resolution, the more ‘features’ that can be revealed, such as types of buildings and other obstructions that might block or weaken radio signals. Each feature identified can then be assigned a ‘clutter class’, carrying its own radio-signal attenuation and absorption values. The more accurate the geodata, the more likely that RF engineers can simulate an accurate picture of the real world using signal-propagation software packages. In this way, they are much better equipped to plot a more cost-efficient rollout of mobile networks.

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THE BEST-LAID PLANS OF 5G

typically delivered to an FTP (file transfer protocol) site. There the data remains static. If clients want an update they have to make another order. It means more hanging around and a greater likelihood that the geodata is well past its sell-by date when it arrives.

“In the future, winners in this space will offer cloud-based solutions that can deliver regularly-updated geodata on an on-demand basis,” says Baffes.

SEEING THE SMALLER PICTUREDigitalGlobe, which has its own satellite constellation and provides geodata on a global scale, says it’s well-positioned to provide the accuracy and refresh-rates that RF engineers crave in their 5G network planning. “The secret sauce that makes our geodata more accurate and detailed is native 50cm resolution,” says Ryan Hamilton, Product Manager at DigitalGlobe.

Most of today’s propagation software, explains Hamilton, is geared to handle 2m resolution data. That’s because software providers generally think that a view of the world, at 2m by 2m pixels, is as good as it gets. They then build their data models with that limitation in mind. Resolution at this level, however, doesn’t contain the rich information found in data created using 50cm by 50cm pixels. Even when DigitalGlobe re-samples its native 50cm data to 2m, so that it can be used by today’s software, those subtle height differentiations and details picked up in 50cm pixels still remain. This gives propagation models a much-needed turbo-boost. Hamilton claims this under-the-hood differentiation provides RF engineers added assurance that heights of buildings and other clutter data are correct.

DigitalGlobe also brings to the table multi-view photogrammetry, a cutting-edge technology that provides much more detail than is possible with traditional stereo photogrammetry. Why? Because it uses a deep stack of overlapping satellite images taken from multiple angles over an area of interest. Hard-to-see areas between tall buildings and the shapes and heights of trees are much more clearly depicted, which all leads to greater precision in 3D modelling. According to Hamilton, this level of

Traditional stereo elevation models derived from satellite imagery are poorly suited for developed areas as the tall buildings often block the view of the stereo pair, leading to lower accuracy and a lack of detail. Multi-view allows for full 3D stereo vision and creates a more accurate and detailed height model used to create realistic 3D vector models.

Stereo digital surface model

Multi-view digital surface model

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accuracy will help plug the information gaps that many RF engineers are wrestling with today.

What’s more, DigitalGlobe’s geodata is worldwide in its scope. It’s also constantly updated. Around three million square kilometers of Earth imagery is fed into the company’s 100-petabyte digital image library — hosted by Amazon Web Services — every day.

This massive library of high resolution imagery is significantly larger than that of any other geospatial data provider, making DigitalGlobe the only company capable of providing abundant opportunity for multi-view photogrammetric tools to quickly access the proper number of overlapping images needed to generate valuable 3D products. And thanks to machine-learning algorithms, these process are continuously improving. But what is truly exciting for the future of this market is that DigitalGlobe plans to provide these meaningful datasets and insights on an on-demand basis. The very same business model that Baffes envisions as being a future winner in this space.

As far as potential software partners are concerned, Hamilton makes a powerful case for close collaboration. Aside from making their 5G models more accurate and compelling for RF engineers,

he argues that an association with DigitalGlobe provides them with a thought-leadership narrative that would not be possible by aligning with other geodata suppliers. “We’re taking our own surplus of raw materials and enhancing them to make something new and unique,” says Hamilton.

DON’T SETTLE FOR THE DEVIL YOU KNOWDespite a general uneasiness about geodata accuracy among RF engineers canvassed in the survey mentioned, many seem reluctant to switch geodata suppliers. Only 5% said they would be ‘highly confident’ when asked how comfortable they would be in adopting a new one.

There may be some natural conservatism at play here — many people, rightly or wrongly, are uncomfortable with change — but, in the case of planning for 5G network rollout, the stakes are far too high to ignore the more accurate 3D-modelling that’s available today. Aside from initial cost savings in hardware and model-tuning during network buildout, RF engineers can reap the benefits of accurate geodata in the post-deployment phase through greater efficiencies in network optimization. Expansion into new markets also becomes much easier.

RF engineers need no longer plan in the dark. l

DigitalGlobe is a leading global provider of high-resolution Earth-imagery products and services sourced from our own advanced satellite constellation and third-party providers. Our geospatial solutions help wireless network operators and service

providers optimize existing RF coverage and plan for the roll out of 5G networks with unparalleled efficiency. DigitalGlobe’s advanced geodata capabilities include 3D vectors, clutter height and elevation information critical for network simulations, and our high-resolution satellite imagery services provide current, accurate, flexible location information for B2B and B2C location-based solutions. Learn more at DigitalGlobe.com.

February 2018