LTE Coverage in downtown Querétaro

A few weeks ago we published the results of measurements of LTE coverage in the main highways of Mexico City. We continue this week presenting the results of the coverage Drive Tests that the Ekspresa team carried out in downtown Queretaro, comparing the operators Altan, AT&T, Telcel and Telefónica.

Measurements were collected using Celplan’s CellWireless multi-technology scanner solution.

We want to highlight that the analysis that we will present in this article is based exclusively on signal levels (RSRP and CINR) measured on LTE cells. This information, although very valuable, does not provide a complete picture of the quality of the user experience on a mobile network.

To perform a complete benchmarking of the quality of service of mobile operators, additional measurements are required using mobile terminals (typically smartphones) performing an extensive test protocol for voice and data services. Even though Ekspresa has extensive experience in this type of project, for this publication we limit ourselves only to measurements collected with the scanner.

LTE coverage evaluation methodology

We followed a similar methodology than the previous study. In summary:

• Date and time of measurement: Saturday, 28-Nov-2020, from 9:00 AM to 2:30 PM.
• Drive tests performed by the engineering team of Ekspresa Mexico.
• Test equipment: Celplan’s Cellwireless solution. CellDigitizer scanner + CellScanner software. Antena of 3.5GHz bandwidth. Equipment calibrated in October 2019.
• Drive test route: Main roads downtown Queretaro.
• Post-processing applying binning by distance. Measurements are averaged within hexagons of an area of 2149m², using Uber’s h3 hexagonal system.
• Frequencies: AT&T 2100MHz (AWS), Altan 700 MHz, Telcel 850 Mhz, 2100 MHz (AWS), 2.6 GHz and Telefónica 1900 MHz.
• We defined a custom “Coverage Level” indicator, combining the RSRP and CINR measurement results. Details here.

Results: What operator has better LTE coverage in downtown Queretaro?

In Fig. 1. a map is shown with the comparison of the four operators for the indicator “Coverage Level” described in the methodology. The map is interactive: you can select the metric to evaluate, change the frequency and/or zoom.

It can be seen that the Altan and Telcel operators have a greater number of samples at level 3. The numerical result can be seen in Fig. 2.

Let’s examine the RSRP and CINR individually:

RSRP comparison

The following figure shows the RSRP statistics for the four operators, where it can be seen that all have more than 98% of the samples above -100 dBm.

If we raise the threshold to -80dBm, we see that Telcel and AT&T take a slight advantage:

Having better RSRP levels favors indoor coverage conditions. In this area, Telcel has better levels within the studied route.

CINR comparison

Comparing the CINR, we can see that Telcel has the largest number of samples above 10 dB, closely followed by Altan.

There are multiple reasons that can affect the level of interference in an LTE network. Among these we have:

• Traffic load in cells. This indicator is modeled by the number of subscribers the network has and the available capacity.
• Reference signal pollution (pilot pollution). The correct planning and optimization of the network helps to minimize this phenomenon.
• MOD 3 interference
• External interference.

The following graph shows the load* measured by CellScanner for the 4 operators. Measurements from all bands are accumulated in a single histogram. We can see that Altan and Telcel have a higher proportion of samples below 50% load. This is consistent with the results in Fig. 5, where we see that these two operators have the best CINR levels.

* Average subframe load from the symbols carrying reference signal

Conclusions

From our study we can conclude the following

• All four operators have good signal strength levels (RSRP). Telcel and AT&T stands out in this area by having a higher percentage of samples above -80dBm, which favors indoor coverage.
• Altan and Telcel have better levels of CINR.
• The main limitation on signal quality for all operators is given by the CINR. This behavior is to be expected given the characteristics of the area (urban environment with a high density of base stations).
• We emphasize that the analysis of signal intensity and interference only provides a partial picture of the performance of a mobile network and the user experience. To carry out an exhaustive comparison between operators, a benchmarking must be made where the different voice and data services are measured.
• The CellWireless spectrum analyzer and scanner solution is a powerful and effective tool for performing this type of coverage analysis on mobile networks.

We have prepared a PDF report with detailed maps by operator and channel. To access this information and the raw data (in plain text format) write to us at info@ekspresa.com or through our contact form to request access.