Outside the building, the smartphone shows 5G and almost full signal strength. A few meters further on – behind the entrance door, in the production hall, or at the latest in the underground parking garage – suddenly only one or two bars remain. In the worst case, it simply means: no network.
What at first glance appears to be a problem with the mobile network provider often has a completely different cause: the building itself becomes a barrier to the radio signals. This is precisely where a professional solution comes in. In-house mobile network coverage to.
Why does good mobile phone reception become a dead zone inside a building?
Mobile phone signals must penetrate various materials on their way into a building. Reinforced concrete, metallic facade elements, and modern thermal insulation glazing can significantly attenuate radio signals. The deeper one moves within a building, the more difficult it becomes to obtain a signal from outside.
This is particularly noticeable in underground parking garages, basements, large halls, or building areas with solid walls. The situation can vary drastically within the same building: while there might be good reception at the window, a stable connection may be nearly impossible just a few rooms away.
„"Then we'll just use Wi-Fi calling" – isn't that enough?
Wi-Fi Calling can be a useful addition. However, it doesn't replace full cellular coverage in every scenario. Visitors first need access to Wi-Fi, not every device supports Wi-Fi Calling, and for numerous mobile applications, IoT devices, or M2M devices, corporate Wi-Fi simply isn't an option.
Furthermore, mobile network coverage works regardless of whether a user is already logged into the local network. This can be crucial, especially in public areas or areas used by many different people.
Simply install a mobile network repeater?
The idea sounds logical at first: there's a signal outside, so it's received, amplified, and rebroadcast inside. In practice, however, a reliably functioning solution requires significantly more.
A professional system must take into account, among other things, which mobile networks and frequency ranges are to be served, what signal quality is actually available at the location, where a suitable donor antenna can be positioned, and how the amplified signal is subsequently distributed within the building.
This also includes cable and distribution losses, antenna positions, signal levels, and the necessary decoupling between outdoor and indoor power supplies. What seems like a simple "signal in, signal out" thus becomes a real radio planning process.
The measurement comes first – not the amplifier.
Before selecting hardware or installing antennas, the initial situation must be understood. Which mobile networks are available outside the building? Which frequency bands reach the location? How do signal levels and quality change inside the building?
Only with this information can a sensible in-house coverage system be designed. A general statement like "one antenna covers X square meters" is therefore not very helpful. Two areas of the same size can have completely different radio requirements.
From floor plan to radio planning
After the inventory is taken, the actual planning begins. Floor plans and building structures help to define the required supply areas and determine sensible positions for the server antennas.
At All-Solutions, we rely on systems from Nextivity CEL-FI and their associated planning tools for planning professional in-house mobile communication solutions. This allows us to analyze building areas, antenna positions, and signal distribution in detail before installation.
Planning involves more than just the antennas themselves. Cable routes, splitters or taps, and the resulting signal attenuation must also be considered. The goal is not to install as many antennas as possible, but to achieve a stable and consistent signal with a properly sized system.
Why more antennas don't automatically mean better reception
In radio technology, more is not automatically better. If antennas are distributed without considering signal levels, overlaps, and system boundaries, a system can become unnecessarily complex without correspondingly improving coverage.
What is crucial is the actual power available at each antenna and the area it can cover under the specific structural conditions. Losses due to cables and passive components are therefore just as important in the planning as the antenna's position on the ceiling.
An underground parking garage is not the same as an office.
A good example is underground parking garages. On a floor plan, they initially appear as large, relatively open spaces. From a radio technology perspective, however, they are anything but trivial.
Low ceilings, reinforced concrete, massive building cores, ramps, and ancillary rooms all affect the propagation of radio signals. At the same time, parked vehicles constantly change the surroundings. An empty driving lane behaves differently than a densely occupied parking area.
Treating an underground parking garage simply like an open hall can therefore lead to unrealistic expectations regarding the range of individual antennas. Conversely, large secondary areas may require significantly more targeted coverage. These differences must be taken into account in radio planning.
And which mobile network is served?
This question should also be addressed at the beginning of any project. In a commercial building, it is often insufficient to consider only a single network operator. Employees, customers, visitors, and service providers use different mobile network providers.
Therefore, the planning process must clarify which operators and frequency bands are required and which signals are available at the location as a starting point. Depending on the requirements, this can result in coverage for one or more mobile network operators.
Plan, install – and then measure
An in-house mobile communications project is not automatically complete once the installation is finished. The crucial factor is whether the planned coverage is actually achieved. Therefore, verifying the actual coverage after installation is essential.
This allows you to determine whether the intended areas are reliably covered and whether adjustments are necessary. Planning and measurement thus form the framework for the actual installation.
In-house mobile communications is radio planning – not simply amplification.
Good mobile network coverage inside buildings is not achieved by using as much amplification or as many antennas as possible. It results from the interplay of measurement, knowledge of the building structure, radio planning, suitable technology, and a final verification.
Whether it's an office building, production hall, warehouse or underground parking garage: If mobile phone coverage is available outside the building, but doesn't work reliably inside, it's worth taking a closer look at the situation first.
Further information on planning, installation and the solutions we use can be found on our services page. In-house mobile communications.
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