Customer case

Calibration of 2G/3G/4G propagation models

Fri 16 Feb 2024

For the customer, this mission enabled more accurate simulation of radio propagation, an important element in mobile network planning and optimisation.

Mobile network planning: Radio propagation model calibration in Sierra Leone

In a telecommunications world where the digital revolution is constant, reliable access to information on the move is a key issue for both users and operators. 
On one hand, there are the users, who want reliable mobile network access to communicate, become culturally aware, entertain, and work. On the other hand, there are the operators, who aim to offer the most efficient network possible to retain their customers.The planning tool is one of the levers for customer satisfaction and investment optimization. Radio simulation is one of the essential components of this tool.
A calibration defect can reduce the accuracy of the propagation simulation and lead to potential regulatory penalties, claims, loss of customer trust, excessive energy expenditure, and even significant health issues.
In this context, calibrating their propagation model allows operators to better predict and stimulate the impact of each antenna in their mobile network.

To enable an operator in Sierra Leone to secure its simulation tools and the strategy depending on them, meet its obligations towards regulators, and avoid all these significant impact setbacks (e.g., network oversizing, lack of coverage, interference observed a posteriori, etc.), Sofrecom was commissioned in 2019 to carry out a Spectrum Clearance & Calibration campaign. This involves a measurement campaign to adjust the model, and a calibration of the different propagation models used by the operator for various technologies such as 2G/3G/4G.

A successful calibration campaign...

The five frequency bands to be calibrated ranged from 800 to 2600 MHz. Initially, a preparatory phase took place to conduct an audit of the existing situation, identify the best approach, and plan the next steps. It was particularly necessary to plan for a number of sites allowing for sufficiently substantial and representative samples of different environments (Urban, Rural, Maritime, etc.). These elements having a direct impact on the simulation, this selection was made in collaboration with the client..

Once all the elements were agreed upon, a field campaign was carried out in several cities and regions of Sierra Leone to reach a total of 20 measured sites. During such missions, we perform Spectrum Clearance and Calibration measurements throughout. This allows us to verify the occupation of all bands, provide elements in case of the presence of devices, especially in the context of exchanges with the regulator and securing measurements, but also to ensure a certain quality of these measurements.

Throughout this mission, a project manager supervised the process from start to finish. Sofrecom's role consisted of:

  • Respecting the required conditions for effective measurements,
  • Providing the technical data necessary for calibration about a week in advance,
  • Calibrating the models using the field measurements performed,
  • Confirming the proper calibration of the models via the validation site measurements,
  • Installing the calibrated models in the client's tools,
  • And finally, managing the client relationship from start to finish.

As part of this mission, deliverables were also transmitted to the client, including a measurement report (photos taken of each site, descriptions, etc.). In a continuous approach of support and professional services, among other things to facilitate the use and reuse of the measurements, training in the use of these new propagation models was provided to the radio engineers of this operator.

 ...With conclusive results

This turnkey project carried out by Sofrecom enabled a complete calibration while respecting the expected quality standards despite a complex project dependent on a number of factors, data sources/quality, site accessibility, execution, health constraints...

The results obtained allowed for precise measurements and the release of the allocated bands for the operator located in Sierra Leone, validating the average noise level of an area and the network bands free of external interference.

For the client, this mission enabled more accurate radio propagation simulation, an important element in mobile network planning and optimization. For Sofrecom, the confirmation of 25 years of experience on the international stage in calibration and our ability to cover all of our clients' issues from start to finish:

  • Strategic audit,
  • Planning,
  • Deployment,
  • Optimization.

El Hassan CHERQI