The Role of 3D Geodata
With the data demand created by smartphone usage, wireless operators deploying advanced 3G and 4G networks in urban areas are utilizing more small cells to delivery capacity and reduce interference.
According to Informa Media and Telecoms, by this quarter their number globally will surpass macrocells.
The analyst firm further predicts 91 million small cells will be in the market by the end of 2016.
Determining the proper location for small cells in urban locations is a tricky business and a case where having the right geodata for the job makes a big difference.
Traditionally, RF planning was accomplished using 2D geodata with a high reliance on clutter classes, and in particular assigning distinct RF parameters per class.
The resolution of geodata employed was typically 25-30m.
This approach worked well where macro sites could propagate from 3-30 km.
However, this approach is does not work effectively in dense urban environments where small cells provide an effective solution for capacity, coverage holes and spectrum-constrained markets.
Image 1 - The above 2D coverage map in a dense urban area based on 25m resolution data is wildly over optimistic given the analysis does not include building data.
What is the impact of this type of site design? A poorly dimensioned network that has coverage holes, interference issues and weak performance.
The inefficiency of using 2D data to simulate urban environments is well known to engineers.
To compensate for this deficiency, many operators rely on the knowledge of experienced planning engineers and site-specific drive-test measurements.
Utilizing drive tests works better, but it's very expensive to perform them frequently with the density required for small-cell deployments.
It's also not practical to perform in-building measurements over a large city-wide area.
Image 2 - Drive-test measurements indicate RF coverage on the road and outside.
As can be seen on the plot above, lack of accurate building contours means in-building coverage problems may be left unaddressed.
Image 3 - Using 3D data, in this case including building polygons at 2m resolution, makes the coverage of the network much clearer.
Note the outdoor small cells located to target indoor coverage holes.
Image 4 - The accuracy of 3D high-resolution data lets engineers fix most of the in-building problems using inexpensive small cells placed outside the buildings, avoiding costly and slow-to-deploy indoor DAS installations.
Many engineers that consider RF simulation as a crude calculation compared with measurements achieved through drive tests have not used high-resolution geodata in conjunction with today's advanced propagation models.
With these highly detailed simulations the precise location of the best placements of small cells is possible when geolocated network traffic and its performance are known.
A major objective for small-cell deployment is not only ad-hoc coverage improvement, but also equally important macro network offload.
A high accuracy, multidimensional small-cell design provides improved macro-network performance, higher customer satisfaction and reduces churn.
Utilizing tried-and-tested processes, as well as urban propagation models and accurate 3D geodata provides engineers with the best opportunity for a successful 4G network design.
For the simulation to be meaningful the geodata utilized must be high resolution (typically under five meters) and it must include building polygons so that urban canyoning effects (e.g., diffraction, reflection) can be accurately reproduced.
By overlaying high-resolution traffic/drops over the detailed predictions, engineers can prioritize the small-cell locations and get the best possible return on investment.
In fact, an investment in 3D data is quickly offset against equipment and optimization costs as the result of a poor initial plan.
Contact us today to learn how ComputaMaps 3D data can help solve your urban network planning efforts.
Special thanks to ComputaMaps partner MobileAllies for the coverage plots. See their optimization service offering using high-resolution data at mobileallies.com