Indoor coverage is one of the biggest challenges for all cellular network operators

Indoor Propagation

CelTrace's Indoor propagation model can be used to model RF propagation inside of buildings, within tunnels and also in a campus environment.


Based on 3D vector databases with planar objects, each with their own individual properties, extremely fast and accurate propagation models can compute path loss and wide-band properties of the radio links inside buildings.


3D IRT (Ray Tracing)

Ray optical propagation models suffer from long computation times. CelTrace’s unique 3D IRT with a single preprocessing of the building data reduces computation times for indoor databases with more than 1,000 objects, to less than a minute. This allows high accuracy and wide-band channel characterization (impulse response, delay spread, etc.) to be combined with fast computation times.


IDP (Dominant Paths)

CelTrace’s Dominant Path Model is the best selection if:

  • Fast and accurate path loss predictions are required
  • Interference with outdoor TRX is important and outdoor coverage in urban or rural scenarios must be computed
  • The database is only available in scanned maps

Multi Floor Predictions

MultiFloorMulti floor buildings require predictions for each floor. CelTrace can compute predictions on an arbitrary number of heights and can display the results in 3D views. This allows for the easy analysis of interference between floors as well as coverage problems on floors without TRX.


Graphical Database Editor

The generation of the building databases was one of the biggest problems for the indoor propagation models for a long time. CelWall, an innovative CAD tool of the CelTrace suite, allows the generation of building databases within a few minutes based on either scanned bitmaps or CAD data (2D and 3D). The user can edit, modify, delete, rotate, move, scale, etc. the objects and define their properties (thickness, colors, materials, electrical properties, etc.)





  • 3D Vector Building Databases
    • Planar objects with polygonal shape (arbitrary number of corners)¬†
    • Individual material properties for each object
    • Subdivisions (e.g. doors, windows) with individual properties
  • Prediction ModelTransmitter Description
    • Tx power
    • Tx frequency
    • Antenna pattern (either 2x2D (e.g. *.msi, *.pln) or 3D (ASCII))

Prediction Models

  • Empirical Models (Direct Ray)
    • One Slope Model
    • Motley Keenan Model
    • COST 231 Multi Wall Model
  • Deterministic Models (Path Searching)
    • Standard Ray Tracing (3D)
    • 3D IRT (Ray Tracing with database preprocessing)
    • 3D IDP (Indoor Dominant Path Model)


  • OutputsMaps (2D) for each prediction height
    • Path Loss / Received Power / Field Strength
    • Delay Spread
    • Angular Spread
    • Propagation Paths
  • Diagrams for each location
    • Channel Impulse Response
    • Angular Profile (DoA for MS and BS)
  • Statistical information
    • Distribution (PDF, CDF) of all maps (total area/parts of area)
    • Mean values and standard deviations¬† (also for comparison to measurements)

Graphical Building Database Editor

  • Editor for Objects
    • Graphical Database EditorCAD user interface (edit, modify, rotate, move, scale, delete, etc.)
    • Definition of subdivisions (e.g. doors, windows, etc.)
    • Assignment of properties to objects (comments, electr. properties, thickness, color, etc.)
    • Multiple 2D views (split screen) for different projections
  • Editor for Materials
    • Assignment of materials to objects individually
    • Predefined material catalogue (different frequencies)
    • User defined material catalogs
  • Conversion
    • DXF files (2D and 3D)
    • Conversion of scanned bitmaps to vector databases


  • GUI: Microsoft Windows
  • Propagation Modules in DLLs for all operating systems (Windows


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