Cloud RF
Understanding Cloud RF
Radio coverage prediction is fundamental to network planning. Before deploying a base station, engineers need to know the coverage area, signal strength at building boundaries, and interference with existing sites. Traditional RF planning tools run on dedicated workstations with locally stored terrain databases, requiring expensive licenses and specialized hardware. Cloud RF shifts this workflow to web-based access, hosting terrain elevation data (SRTM at 30 m resolution globally, LiDAR at 1 to 2 m where available) and clutter databases in the cloud, eliminating local storage and compute requirements.
The platform's propagation engine evaluates signal strength at each point in a grid by computing free-space path loss, terrain diffraction (using Bullington or Deygout methods along the terrain profile between transmitter and receiver), atmospheric absorption, and clutter loss (building, forest, suburban categories each with empirical attenuation values). For a typical macro cell coverage calculation at 1,800 MHz with 100 m grid resolution over a 10 km radius, the engine evaluates approximately 31,000 grid points, each requiring a terrain profile extraction and propagation model computation. Cloud parallelization completes this in 2 to 10 seconds versus 30 to 120 seconds on a desktop, with the ability to run hundreds of sites simultaneously for network-wide interference analysis.
Propagation Model Equations
FSPL = 32.45 + 20log(fMHz) + 20log(dkm) (dB)
Knife-Edge Diffraction Loss:
Ld = 6.9 + 20log(√((ν - 0.1)² + 1) + ν - 0.1) for ν > -0.78
Received Power:
Prx = Ptx + Gtx - Lcable - FSPL - Ldiff - Lclutter + Grx (dBm)
Where ν = Fresnel-Kirchhoff diffraction parameter = h√(2/(λd1d2/(d1+d2))), h = obstacle clearance height, d1,d2 = distances to obstacle, λ = wavelength. FSPL at 1800 MHz, 1 km = 105.5 dB.
Propagation Model Comparison
| Model | Frequency Range | Distance | Accuracy (std dev) | Best For |
|---|---|---|---|---|
| ITU-R P.1812 | 30 MHz to 6 GHz | Up to 10,000 km | 6 to 10 dB | General terrestrial planning |
| Longley-Rice (ITM) | 20 MHz to 20 GHz | 1 to 2,000 km | 8 to 12 dB | Rural, irregular terrain |
| ITU-R P.526 | 30 MHz to 30 GHz | LOS + near-LOS | 4 to 8 dB | Diffraction over obstacles |
| Okumura-Hata | 150 MHz to 1.5 GHz | 1 to 20 km | 8 to 12 dB | Urban/suburban cellular |
| COST 231 Walfisch-Ikegami | 800 MHz to 2 GHz | 0.02 to 5 km | 6 to 10 dB | Dense urban micro cells |
Frequently Asked Questions
What propagation models does Cloud RF support?
ITU-R P.1812 for general terrestrial planning (30 MHz to 6 GHz, up to 10,000 km). Longley-Rice (ITM) for irregular terrain (20 MHz to 20 GHz). ITU-R P.526 for knife-edge and Bullington diffraction. Okumura-Hata and COST 231 for empirical urban/suburban cellular planning. Each model suits different frequency ranges, environments, and accuracy requirements.
How accurate are cloud-based propagation predictions?
With 30 m SRTM terrain and basic clutter, median prediction error is 8 to 12 dB standard deviation versus drive tests. High-resolution LiDAR (1 to 2 m) with building databases reduces this to 4 to 8 dB. Largest error sources are building penetration variability (10 to 25 dB) and foliage loss uncertainty. For planning, 6 to 8 dB accuracy is sufficient given 8 to 15 dB fade margins.
How does Cloud RF compare to desktop planning tools?
Desktop tools (Atoll, ASSET, EDX SignalPro) offer 3D ray tracing and traffic modeling but cost $10K to $50K per seat. Cloud RF provides web access at $10 to $200/month with API automation and no terrain data storage. For large networks (1000+ sites), desktop tools are superior. For rapid feasibility, small networks, and field engineering, Cloud RF offers faster results at lower cost.