Prediction system for RF power distribution

• US 5,949,988 A
• Filed: 04/03/1997
• Issued: 09/07/1999
• Est. Priority Date: 07/16/1996
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Raukumar, Ajay, Feisullin, Farid, Rogers, Lois, Naylor, Bruce
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): Phan, Thai
• Application Number:
  US08/838,221
• Time in Patent Office: 887 Days
• Field of Search: 364/578, 395/500, 342/359, 343/703, 455/52.3
• US Class Current: 703/2
• CPC Class Codes: H04B 17/0082 using service channels; using auxiliary channels
• CPC Class Codes: H04B 17/391 Modelling the propagation channel
• CPC Class Codes: H04W 16/18 Network planning tools

Abstract

A method for simulating RF energy distribution comprises obtaining a binary tree representation of a geometric environment in three-dimensions and forming a 3-D geometric database model therefrom, obtaining one or more specified receive locations within the 3-D geometric database model where RF energy distribution is desirable, simulating the propagation of an RF signal within the geometric database model, the RF signal being represented as a beam having magnitude and direction, the propagation including querying the database model to trace the beam in the geometric environment; and, determining one or more intersections of the traced beam with one or more receive locations to determine RF energy distribution at the receive locations.

Claims

1. A method for simulating RF energy distribution comprising:

a) obtaining a binary tree representation of a geometric environment in three-dimensions and forming a 3-D geometric database model therefrom;

b) obtaining one or more specified receive locations within said 3-D geometric database model where RF energy distribution is desirable;

c) simulating the propagation of an RF signal within said geometric database model, said RF signal being represented as a beam having magnitude and direction, said simulation including querying said database model to trace said beam in said geometric environment; and

,

d) determining one or more intersections of said traced beam with one or more receive locations to determine RF energy distribution at said locations.

2. A method for simulating RF energy distribution according to claim 1, wherein said step of providing a binary tree representation of said geometric environment includes the steps of:

obtaining knowledge of a geometric environment in three-dimensions; and

partitioning said geometric environment in three-dimensions and modelling said environment as a binary tree, said binary tree containing nodes representing partitions of said geometric environment and leaves representing partitioned regions in said geometric environment.

3. A method for simulating RF energy distribution according to claim 2, wherein said partitioning step includes incorporating hyperplanes to represent surfaces of objects in said geometric model.

4. A method for simulating RF energy distribution according to claim 2, wherein said partitioning step includes the step of classifying said region leaves as in-cell regions representing inside an object in said environment and out-cell regions representing a region outside an object in said environment.

5. A method for simulating RF energy distribution according to claim 4, wherein said simulating step c) includes the step of determining an intersection of said beam with an object in said environment, said beam being represented as a ray having magnitude and direction, and said intersection occurring when said representative ray goes from an out cell leaf classification to an in cell leaf classification or from an in cell leaf classification to an out cell leaf classification.

6. A method for simulating RF energy distribution according to claim 5, further including the step of determining beam extents for said intersecting beam, said beam extents determined by calculating a solid angle for said beam and determining an angle of incidence its representative ray makes with said intersected object.

7. A method for simulating RF energy distribution according to claim 5, wherein said step of determining an intersection of a beam with an object in said environment includes determining magnitude and direction of its representative ray reflected from and a ray transmitted through said object, and further simulating the propagation of corresponding reflected and transmitted beams in said environment.

8. A method for simulating RF energy distribution according to claim 7, wherein said step of determining magnitude and direction of a reflected beam includes determining angle of incidence between its representative ray and said object, and attenuating said beam in accordance with material attributes of said intersected object.

9. A method for simulating RF energy distribution according to claim 6, further including the step of determining whether said beam has intersected an edge of said object, said step further including determining a distribution of rays representing beams diffracting from said edge and further simulating the propagation of each said diffracting beams in said environment.

10. A method for simulating RF energy distribution according to claim 1, wherein said simulating step c) further includes:

e) determining intersections of said beam with objects in said environment;

f) comparing a magnitude of a current intersecting beam with a user-defined threshold; and

, repeating steps e) and f) until the magnitude of a current intersecting beam is below said threshold.

11. A method for simulating RF energy distribution according to claim 1, wherein said step of obtaining one or more specified receive locations within said 3-D geometric database model includes obtaining one or more specified RF power sampling planes for integration in said model.

12. A method for simulating RF energy distribution according to claim 11, wherein each of said one or more RF sampling planes are at multiple heights in said environment.

13. A method for simulating RF energy distribution according to claim 11, wherein said step d) of determining an intersection of said beam includes the steps of:

determining intersection of its representative ray with said RF power sampling plane;

calculating extents of said beam;

determining from said extents coverage of said beam at said one or more receive locations; and

,

recording an RF power level at each said one or more receive locations.

14. A method for simulating RF energy distribution according to claim 13, wherein said step of calculating beam extents includes the step of calculating a solid angle for said beam and determining an angle of incidence its representative ray makes with said RF sampling plane.

15. A method for simulating RF energy distribution according to claim 6, wherein said simulating step further includes the step of subdividing said beam into child beams and simulating the propagation of each child beam within said environment, said subdividing step including partitioning an extent area according to current beam power and distance its representative ray has travelled since a previous intersection or originating point.

16. A method for simulating RF energy distribution according to claim 6, further including the step of representing said geometric environment in a first coordinate system, the simulating step including representing said beam as a ray for propagation from an origin within said first coordinate system.

17. A method for simulating RF energy distribution according to claim 16, wherein the step of computing beam extents includes computing a solid angle for said beam in a second coordinate system.

18. A method for simulating RF energy distribution according to claim 6, wherein said simulating step further includes the step of specifying the location of a beam originating transmitter within said database model from which said beams propagate from.

19. A method for simulating RF energy distribution according to claim 18, further including the step of obtaining a specified transmitter antenna type and gain pattern.

20. A method for simulating RF energy distribution according to claim 19, wherein said transmitter antenna is represented as an antenna surface, said method further including tessellating said antenna surface in order to determine initial beam extents for each propagating beam.

21. A method for simulating RF energy distribution according to claim 20, wherein said transmitter antenna surface is tesselated as a plurality of polygonal shapes, said beam extents calculated in accordance with said polygonal shape.

22. A method for simulating RF energy distribution according to claim 1, wherein said geometric environment includes an indoor environment.

23. A method for simulating RF energy distribution according to claim 1, wherein said geometric environment includes an outdoor environment.

24. A method for simulating RF energy distribution according to claim 1, wherein said geometric environment includes a terrain environment.

25. A method for simulating RF energy distribution according to claim 1, wherein said geometric environment includes a combination of two or more of indoor, outdoor, and terrain environments.

26. A system for simulating RF energy distribution comprising:

a) means for obtaining a binary tree representation of a geometric environment in three-dimensions and forming a 3-D geometric database model therefrom;

b) means for obtaining one or more specified receive locations within said 3-D geometric database model where RF energy distribution is to be determined, said means further obtaining locations of one or more specified RF transmitters within said 3-D geometric database model, said transmitters for propagating an RF signal represented as a beam having magnitude and direction;

c) means for querying said database model to simulate the propagation of said beam in said geometric environment; and

,

d) means for determining one or more intersections of said beam with one or more receive locations to determine RF energy distribution at said locations.

27. A system for simulating RF energy distribution according to claim 26, wherein said obtaining means further obtains specified parameters for controlling the RF simulation, said specified parameters including a type of antenna transmitter, an antenna gain pattern, and an RF transmitter frequency.

28. A system for simulating RF energy distribution according to claim 26, wherein said obtaining means further obtains specified material attributes for objects modelled in said 3-D geometric database model.

29. A system for simulating RF energy distribution according to claim 26, wherein said obtaining means includes an interactive display device enabling a user to visualize said geometric environment in three-dimensions.

30. A system for simulating RF energy distribution according to claim 26, wherein said interactive display device includes means for enabling a user to specify one or more of said receive locations within said displayed geometric environment and to specify said locations of one or more RF transmitters within said displayed geometric environment.