3 QUESTIONS ABOUT RADIO-MAPPING

To Nicolas Maurice, IoT technical expert

Radio mapping is an essential step in any IoT project with an LPWAN network. It ensures the success of the project in the field. It also helps avoid disappointments when deploying sensors on site or afterwards.

Nicolas Maurice, technical expert at Adeunis, explains why it is essential to carry out a radio coverage study.

What is radio-mapping?

This is a study that allows us to determine the coverage quality of a LoRaWAN or Sigfox IoT network in an area. This study is carried out in the area where IoT sensors are to be installed in the future. This is done in order to verify the possibilities of deployment and to validate the correct implementation of the use cases envisaged. For example, to check the network coverage in a boiler room where adeunis TEMP temperature sensors will be deployed on a domestic hot water network.

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In the case of a private network deployment, this study can also be carried out in order to determine the positioning of the gateway(s) iin the building according to the points to be measured.

This survey is carried out on site, using the adeunis network tester, the FTD (Field Test Device). The FTD determines the availability of the network at various measurement points. The data can be viewed directly on the digital display and also recorded for later analysis.

When to carry out a radio-mapping study?

There are two categories of studies:

The first is done at the beginning or upstream of the project to qualify the environment in which you are located. What network is available? How is the coverage? Which points are at the limit of coverage?

The second is done when the sensors are deployed on site, to validate the exact positioning desired for the devices and/or the gateway.

Step 1: On-site network qualification

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In the first stage of network qualification on site, two approaches coexist:

  • Or the radio coverage of the site is completely unknown. The project manager then wishes to determine which IoT networks are available and efficient on his site.
  • Or the project manager has already determined the network on which he wishes to deploy his use cases. He will then carry out a radio-mapping study to confirm this choice. Depending on the need, he will also be able to identify whether it is necessary to switch to a private network or to set up equipment to extend the range of the existing operated network.

In this “pre-project” phase, the radio-mapping study helps to shed the light on the choice of network. The data is to be combined with other elements to meet the needs of the IoT project and its objectives.

Examples of elements to take into account when choosing the type of network to use for your IoT project:

  • volume of data to be communicated,
  • frequency of data communication,
  • degree of criticality of the information,
  • level of deliverability,
  • level of security,
  • geographical area,
  • extent of sensors,
  • need for autonomy,
  • one or two way communication,

Step 2: On-site deployment

During the on-site deployment phase, the network study allows us to define and validate:

  • the exact positioning of the IoT sensors,
  • the positioning of the gateways or repeaters.

Indeed, depending on the type of location (number of floors, materials making up the building or the equipment present, location with respect to antennas), not all locations have the same access to the network. For example: it is common to have to place sensors in the basement on meters or equipment such as boilers. In the basement, access to the network is very often more limited.

As another example, the adeunis team of experts recently carried out a radio-mapping of about 100 points on a site of several square kilometers. This site included underground meters to be monitored. For such a site, three gateways were finally necessary to ensure complete coverage of the site.

How does radio-mapping work?

  • In the case of a private network, the distribution of the locations and the desired positioning of the IoT sensors are first studied on a map. The theoretical position of the gateway(s) is then determined.

We then go to the site, where we position and activate the gateways. Then, thanks to the FTD, measurements are carried out on the envisaged sensor locations. The positioning of the gateway or transmitters is then adapted accordingly.

  • In the case of an operated network, we go directly to the site to carry out measurements point by point where the sensors will potentially be positioned.

Finally, the data is recorded and retrieved for later analysis. They will then be used to draw up a study report with all our recommendations and guidance.

In short, deploying hundreds of LPWAN sensors without validating the coverage in the field means almost certainly having to return to the site afterwards and therefore reducing the return on investment of the project.

The FTD is the essential tool for carrying out this study. In addition to its use, only an in-depth analysis of the data collected and meticulous field tests, carried out by experts, can fully validate and consolidate the feasibility of the project.

The radio-mapping study therefore makes it possible to quickly identify weak points in the network and to plan, from the outset, corrective solutions to optimise the deployment of the project and guarantee the correct transmission of data.

24/04/2021

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