In today's interconnected world, reliable wireless connectivity has become an essential aspect of modern indoor environments. Whether it's in offices, schools, or homes, seamless WiFi coverage is crucial for enabling seamless data transfer, video conferencing, and a plethora of other online activities. However, achieving consistent and reliable WiFi coverage can be a challenge due to various factors, including building structure, wall materials, furniture placement, and interference from other electronic devices.

Traditional methods for WiFi access point (AP) placement often rely on manual site surveys and calculations. While these methods can be effective in certain situations, they can be time-consuming, error-prone, and may not accurately reflect the complex geometry and material properties of the building environment.

A more comprehensive and data-driven approach to WiFi AP placement involves utilizing Building Information Modeling (BIM) and wave propagation simulation. BIM provides a detailed and accurate digital representation of the building, including floor plans, wall materials, and furniture arrangements. Wave propagation simulation software, on the other hand, allows for the analysis of signal strength and coverage throughout the virtual building model.

To illustrate the effectiveness of this approach, consider a case study involving an office building. A BIM model of the building was created, and wave propagation simulation was performed to analyze the signal strength and coverage throughout the building. The results of the simulation were used to identify optimal AP locations.

BIM Modelling

To optimize the placement of Wi-Fi AP inside the building module of dimension 3 m x 9 m as show in Fig. a parametric electromagnetic wave propagation simulation for propagation, scattering and attenuation of Wi-Fi signals is carried out. The Wi-Fi hotspot is varied in x-direction from 0.5 m to 4.5m and a detailed simulation of is performed by solving Helmholtz equation. It is a subset of Maxwell equation that is typically sued to model wave behavior in steady state electromagnetic fields

Simulation

The simulation for Wi-Fi signal propagation is conducted by solving the Helmholtz equation. A PDE solver in MATLAB is utilized to solve the equation in the domain and boundary conditions present in the BIM model. To determine the spread of Wi-Fi signal the norm of the mean energy is utilized. It used as an indicator of the proper propagation of Wi-Fi signal over the domain of the problem.

$$\nabla^2 u + k^2 u = 0$$

$$\begin{equation} \int_{\Omega} (\nabla u \cdot \nabla v - k^2 u v) \, dx = 0 \quad \forall v \in H^1(\Omega) \end{equation}$$

Result

The WiFi signal strength increases as the AP is moved further away from the walls, up to a certain distance where it starts to decrease again. This is because the signal strength is less affected by the walls when the router is further away, and is able to propagate more freely. The walls at the edge of the room reflect and absorb some of the signal, causing it to weaken. Therefore, the optimum location to place the router is at the distance where the signal strength is at its maximum, given the arrangement of walls in the room. This location provides the best balance between signal strength and coverage.