University Federico II of Napoli (Italy)

1. Numerical and Graphical Solvers for Urban Propagation Daniele Riccio University Federico II of Napoli (Italy)

2. Numerical and Graphical Solvers for Urban Propagation Daniele Riccio Joint work with: Giorgio Franceschetti Antonio Iodice Giuseppe Ruello University Federico II of Napoli (Italy)

3. 1° 2° 3° Approaches to solve a problem (1) • In the Academy… Theory Solution Resources

4. 1° 2° 3° Approches to solve a problem (2) • In a Company… Resources Solution Theory

5. 1° 2° 3° Approches to solve a problem (3) • Mixed way Solution Resources Theory

6. Which is the problem? • Plan the radio coverage for a wireless network operating in an urban area Solution = Maxwell Equations + constitutive relationships + boundary conditions + initial conditions No simple solution for complex environments

7. What sort of network? • It depends on your boss: Example plan UMTS Italy ≈ 10000 Base stations 1-Owner of a large company → Example plan UMTS Capri 1-3 Base Stations 2-Director of a local division →

8. 1-The boss is the owner of a large company

9. 2-The boss is the director of a local division

10. Stochastic or Deterministic approach? Example plan UMTS Italy ≈ 10000 Base stations Stochastic 1-Owner of a large company → Example plan UMTS Capri 1-3 Base Stations Deterministic 2-Director of a local division →

11. Deterministic approachWhat do we need? • Solutions → Software Tools for: • Antenna (or antennas) optimal location • Position • Orientation • Input power • ……. • Antenna optimal parameters • Radiation patterns • Input power • ……. • Best server • ………… Does it exist one “core” software tool (CoreST)?

12. What problem can the “core” tool solve? … over a prescribed scene For a prescribed antenna… Evaluation, in the phasor domain, of the radiated field

13. Which is the problem, now? • Evaluate, in the phasor domain, the radio coverage for a wireless network operating in an urban area Solution = Maxwell Equations + constitutive relationships + boundary conditions No exact analytical solutions for complex environments

14. What can I do with the electromagnetic field prediction? • Increase SNR • Increase channel capacity • Reduce the cost for bandwith • Reduce biological effects

15. Is there any other problem that can be solve? • GSM planning • UMTS multipath • Mobile • WLAN • indoor

16. CoreST rationale • Deterministic Approach • Direct ray tracing • 3D scansion Only some years ago following such a strategy was consideredto be IMPOSSIBLE

17. PROPAGATION: RAY TRACING TECHNIQUES Microwaves Geometrical Optics Two kinds of ray tracing algorithms • Inverse Algorithms (proper ray tracing) – all feasible paths between site and receiver are explored, and field value at receiver is calculated from contributes. • Direct Algorithms (ray launching) - rays span the scene and are followed until a threshold value is reached. At each sample point field is evaluated. Pros: faster, e.g. graphic 3D rendering Cons: only feasible for end-to-end links Pros: accuracy, global computation (Best Server, Network Planning ) Cons: computation load

18. Program rationale Electromagnetics Reflections Geometric optics approximation Scattering Classical or fractal electromagnetic models Diffractions Diffractions are evaluated by means of the most advanced UTD techniques

19. Program rationale End of program Procedure stops when the field level undergoes a sensitivity threshold Output The whole field value map is provided as well as a coverage map.

20. Program rationale Horizontal plane (HP) - Vertical plane (VP) Buildings have vertical walls Radiation diagrams are projected on HP and VP HP projection. VP projection

21. Algorithm rationale Horizontal plane analysis • Input Data : • Antenna table • Position, rad. diagr., … • Building table • Vertex position, height, e, ...

22. Algorithm rationale Horizontal plane analysis • Pixel Scanning • For each pixel: • evaluate its polar coordinates, assign the pixel to an anxel.

23. Algorithm rationale Horizontal plane analysis Building scanning For each wall: assign the wall to anxels (and evaluate distances); For each vertex: evaluate its polar coordinates, assign the vertex to an anxel.

24. Algorithm rationale Horizontal plane analysis • At the end of the scanning: • for each anxel we have three lists, sorted by distance from the source: • pixels list, • walls list, • vertexes list.

25. Algorithm rationale Vertical plane analysis For each anxel: Vertical plane analysis. Scanning (from lower to higher distances from the source) of “objects” in the anxel: pixels, walls and vertices (wedges).

26. Algorithm rationale Accuracy dependence on anxel width

27. INPUTS CONTROL AND CHECK TOPOGRAPHY ANTENNA SCENE ELECTROMAGNETIC PARAMETERS

28. Inputs

29. Inputs

30. Inputs

31. Inputs

32. Inputs

33. Inputs

34. Inputs

35. Inputs

36. Acknowledgment WISE – WIde SEnsing

37. Resources – InputMan power in months

38. OUTPUT: Numerical • 7 matrixes, related to the calculation at street level and on the rooftops: • (complex) • (real) • summations extended to the number of rays which arrive to the point with a field • level upper than the threshold • (real) • for each building, 1 vector, with length equal to the number of floors (only last simulation) • comparison with the measured field in the points of the raster where it is available • |Etot| in raster geo-referred format file for later comparisons with other simulations • rate between the power of the strongest channel and the sum of all the others iso- frequency in the superposition areas ( C/I ) • Measure units: Volt/m, Watt/m2, dBmVolt/m, dBmWatt/m2

39. OUTPUT: Display • for street level, building floor and roof: • Layers management ( Prediction , Buildings, Measure ) • Color options (Grey levels / Rainbow colors, Gamma correction) • Zoom • 2D / 3D visualization • |Etot|, in false colors or grey levels • |Ex|, |Ey| and |Ez|, in color levels (RGB) • Ex, Ey and Ez numerical value readable moving the mouse on the map • Best Server • the points where the measured field is available (read by file) Tools:

40. Output

41. Output

42. Resources – OutputMan power in months

43. OperationalModes • Single Source (Single map, single antenna) • Coherent and incoherent field levels, related to the area illuminated by the antenna. • Interference (Single map, up to three antennas) • Incoherent field related to the different antennas, individuation of the antenna • which better serves each point , superposition areas, C/I. • Best Server (Single map, more than three antennas) • Best server. • Measured values (Single map, single antenna) • Position of the points on the map, numerical values, comparison with predicted values.

44. SPEED UP: IDL BUILT-IN FEATURES All-in-one math operations on arrays: E.g.: polar to Cartesian coordinates • for i=1,Nmax do begin • for j=1,Mmax do begin • xcoord[i,j]=r[i,j]*cos(teta[i,j]) • ycoord[i,j]=r[i,j]*sin(teta[i,j]) • endfor • endfor xcoord=r*cos(teta) ycoord=r*sin(teta) Speed up: 15 x - 50 x 1,1 1,2 … 2,1 … … … … n,n

45. USER-LEVEL FLOW CHART Coherent vectorial field (/L >> 1) Diffracted rays interactions Outdoor field calculation Planet file: Incoherent vectorial field (/L << 1) Terrain Profile Buildings Map Buildings E.M. data More Sites? Diffracted rays Indoor field calculation Total field power Graphic interface: Reflected rays yes Site location Rx threshold Simulation options Measured field comparison Direct rays Antenna Planet file: Irradiation pattern Polarisation pattern New site location Antenna parameters Simulation options

46. IMPROVEMENTS IN-PROGRESS (2) LIFO discipline in source handling Less memory requirements Source Loading Ray tracing

47. POLARISATION Antenna polarisation input parameter Propagation E E, E referenced to ray E Reflection/Diffraction E, E// referenced to surface E// E Ez Output Ey Ex, Ey, Ez in UTM reference Ex

48. GIS GIS aimed investigation • How to operate on spatial data?  Computational geometry • How to manage data?  DBMS • How to export data to GISs?  Tiff Geo-data

49. PROPAGATION: a simple example… …of how LOS coverage changes depending on terrain profile:

50. PROPAGATION: DTM shading • Terrain profile influences radio propagation in GO model: Reasonable diffractive contribution from natural edges? No field because of closer to source points The building is now partially out of LOS