Case Study: A Deterministic Approach to mmWave FWA Qualification
By Brett Mills-Meiner, Head of Product for Cloud Software
In December 2024 Pivotal was allowed to test for mmWave signal inside a vacant apartment in a 23-unit MDU in the Queen Anne neighborhood of Seattle. The apartment unit was 100 meters away from a gNB, but line-of-sight (LOS) was blocked by a nearby concrete building. Pivotal validated a surprising prediction by its network modelling tool, WaveScape™, which suggested that the units in the MDU have sufficient coverage for Fixed Wireless Access (FWA). WaveScape’s high-resolution analysis identifies beam paths for FWA qualification instead of relying on statistical pathloss modelling. This blog explains how WaveScape’s approach gives a clearer picture upon which to base this decision.
Figure 1 Left: Screenshot from Google showing target apartment (C), reflecting building (B), gNB and LOS blocker building between the gNB and C. Right: Screenshot from RayViewer showing predicted geometry of the reflected link
The Set-Up
Figure 1 (left), above, shows that the face of the MDU (C) does not have LOS to the mmWave gNB. Standard 5G mmWave modelling tools would disqualify the entire building based on this fact alone. However, WaveScape’s high-resolution ray-tracing model, Reverb™, identified a reliable reflection from a building (B) across the street that provided sufficient signal strength for FWA. Reverb’s new RayViewer™ feature, shown in Figure 1 (right), allows carriers to easily visualize and validate how the signal can reach the subscriber.
WaveScape Predictions
WaveScape predicts signal strength and angle-of-incidence on the surface of buildings to determine which places on the building face can support FWA and how much out-to-in penetration loss through glass the link can support. By combining these signal strength predictions with readily available apartment layout data, WaveScape can identify the individual apartment units in the MDU that can support FWA. In this scenario, WaveScape determined that all west-facing units above the third floor had sufficient signal for FWA with up to 35dB glass-loss. Because WaveScape used 15cm resolution data to identify this link path, the tool can take advantage of the deterministic nature of mmWave propagation and confidently make predictions even in a non-line-of-sight (NLOS) scenario.
Measurements Inside the Apartment
To validate WaveScape’s predictions, Pivotal took measurements with both the window closed and open. Consistent with WaveScape’s predictions, the window-open signal strength was -61dBm RSRP, and the window-closed signal strength was -93dBm. Pivotal’s Software Product Director, Brett Mills-Meiner (pictured in Figure 2), is shown using industry-standard CPE to test the connectivity speeds. He achieved download speeds greater than 500 Mbps on mmWave with the window closed. Now that the glass loss for the building is better understood, Pivotal’s predictions about future units in this building can be more refined and accurate.
Figure 2: Measuring different RSRP values, one acceptable, one not, at the same window.
Qualifying MDUs for mmWave FWA
WaveScape, through its Reverb ray tracing model and RayViewer’s propagation visualization, can help carriers take advantage of the deterministic nature of mmWave propagation. These are enabled by the high-resolution nature of WaveScape so that it can rely on physical realities to model mmWave, not just statistics. Finally, WaveScape’s ability to join MDU building floorplans can help carriers monetize existing mmWave assets by turning deterministic coverage predictions into happy subscribers.