Modeling of RF point source reference for analysis of wireless signal propagation

• US 7,313,391 B2
• Filed: 09/14/2001
• Issued: 12/25/2007
• Est. Priority Date: 09/26/2000
• Status: Expired due to Fees

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Andrew Corporation (CommScope Holding Company, Inc.)
• Inventors: Gutowski, Stanley J.
• Primary Examiner(s): Gauthier; Gerald
• Application Number:
  US09/951,503
• Publication Number:
  US 20020063656A1
• Time in Patent Office: 2,293 Days
• Field of Search: 455/9, 455/10, 455/13.4, 455/39, 455/67.13, 455/67.14, 455/68, 455/69, 455/107, 455/114.2, 455/114.3, 4551151-1153, 455/127.1, 455/127.2, 455/450, 455/452.1, 455/452.2, 455/455, 455/456.1, 455/456.2, 455/517, 455/522, 455/277.1, 455/423, 455/448, 455/456.5, 342/360, 342/458, 375/130, 375/352
• US Class Current: 455/423
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A data collection and evaluation method for determination of wireless signal propagation from an incomplete set of measured data and for modeling the system as a set of RF point sources located at the tower in each cell. RF propagation measurements are collected according to the present invention, by moving through the wireless system while collecting signal strength data at a large number of locations throughout the wireless system. Signals are received from multiple antennae at each collection location. The present invention develops a non-directional RF propagation model based upon the signals received from each antenna at a particular cell site, the antenna directionality due to the design of the antenna and the orientation of the collection location and the cellular site. The digital identification information on the channel is decoded and used to associate the measurement with an individual originating wireless antenna and/or sector. The decoding process is limited by interference and low signal levels, therefore, the resulting data will have locations or entire areas where digital identification codes cannot be determined and the signal origination antenna cannot be identified. The RF propagation data is then analyzed to remove directionality of the individual antennae and to determine the absolute value of the path loss between the tower as an RF point source and a specific geographic location.

Claims

1. A method for determining an RF propagation pattern for a sector comprising:

collecting signal data throughout the sector, the signal data defining a plurality of signals having a respective signal strength value at a collection location;

identifying an originating antenna for each of the plurality of signals received at the collection location;

determining a path loss value for each signal; and

normalizing the path loss value to obtain the normalized path loss value for each signal by combining the signal strength values of signals received from one or more antenna directed toward the collection location with signal strength values of signals received from one or more antenna not directed toward the collection location to determine an RF propagation pattern for the sector.

2. The method of claim 1, wherein identifying the originating antenna further comprises decoding each received signal to identify the originating antenna.

3. The method of claim 2, wherein at least one of the plurality of signals is a beacon signal.

4. The method of claim 2, wherein decoding each received signal further comprises associating a channel/color code detected from the signal with a known combination of a particular antenna.

5. The method of claim 1, wherein identifying the originating antenna further comprises keying-up a test channel for propagating a signal into the collection location.

6. The method of claim 1, wherein collecting signal data throughout the sector further comprises conducting mobile data collection through a sector.

7. The method of claim 1, wherein normalizing path loss value removes the effects of the directionality of the originating antenna.

8. The method of claim 1, wherein normalized path loss is a function of distance of the collection location from the originating antenna and antenna characteristic.

9. The method of claim 8, wherein the antenna characteristic is defined by at least one of directional gain of antenna, location of antenna, RF mount, RF path, boresight, mechanical tilt and the electrical tilt of the antenna.

10. The method of claim 1, wherein collecting signal data further comprises using a scanning receiver tuned to a first frequency.

11. The method of claim 1, wherein the antenna not directed toward the collection location includes antenna facing away from the collection location.

12. The method of claim 1, wherein the signal received from the antenna not directed toward the collection location further comprises signals received at the collection location as backscatter or side scatter.

13. The method of claim 1, wherein each of the plurality of signals is normalized independently.

14. A method for determining signal strength at a location within a sector of a wireless communication system comprising:

measuring signal strength of a plurality of incoming signals having a common frequency at a location, the signal strength including contributions from backscatter and antennas facing away from the location;

identifying an originating antenna associated with each of the incoming signals;

determining a path loss value for each of the originating antennas; and

normalizing the path loss value for each of the originating antennas as a function of a characteristic of the originating antenna by determining a combined signal strength as a function of the measured signal strength from each of the plurality of incoming signals and the normalized path loss value for each respective signal.

15. The method of claim 14, wherein measuring signal strength further comprises decoding each received signal to identify the originating antenna.

16. The method of claim 15, wherein decoding each received signal further comprises associating a channel/color code detected from the signal with a known combination of a particular antenna.

17. The method of claim 14, wherein the incoming signal is a beacon signal.

18. The method of claim 14, wherein identifying the originating antenna further comprises keying-up a test channel for propagating a signal into the collection location.

19. The method of claim 14, further comprising determining signal strength at a plurality of locations throughout a sector to define a propagation model of the sector.

20. The method of claim 14, wherein measuring signal strength further comprises using a mobile receiver traveling through a known path within the sector.

21. The method of claim 14, wherein the antenna characteristic is defined by at least one of directional gain of antenna, location of antenna, RF mount, RF path, boresight, mechanical tilt and the electrical tilt of the antenna.

22. The method of claim 14, wherein the path loss is determined as a function of antenna design, directionality and orientation.

23. The method of claim 14, wherein measuring signal strength further comprises establishing a collection route through the sector for collecting signal strength data.

24. The method of claim 14, wherein measuring signal strength further comprises using a scanning receiver tuned to a first frequency.

25. The method of claim 14, wherein the signal strength of a signal includes signal propagation from antenna sidescatter.

26. The method of claim 14, wherein each signal from each antenna is normalized independently.

27. A method for determining signal strength contour for a cell site within a cellular communication network, the method comprising:

receiving a plurality of signals at a plurality of locations within the communication network;

for each received signal, identifying a signal strength value as a function of the propagation direction of a respective originating antenna in a sector, the originating antenna including an antenna facing away from said sector and an antenna located in an adjacent sector;

determining an absolute value of the signal strength; and

defining a signal strength contour for the cell site as a function of the absolute value of the signal strength and the plurality of locations within the communication network.

28. The method of claim 27, wherein the antenna facing away from said sector propagates backscatter and sidescatter signals.

29. A system for determining an RF propagation pattern of a sector comprising:

an RF scanner;

a processor coupled to said RF scanner, said processor programmed with instructions to;

direct the RF scanner to receive signal data throughout the sector, the signal data defining a signal strength at a collection location;

identify an originating antenna for the received signal at each collection location;

determine a path loss value for each received signal;

normalize the path loss value to obtain the normalized path loss value for each received signal;

combine signals received from one or more antennas directed toward the collection location with signals received one or more antennas directed away from the collection location to determine an RF propagation pattern for the sector.

30. The system of claim 29, wherein identifying the originating antenna further comprises decoding the received signal to identify the originating antenna.

31. The system of claim 30, wherein the received signal is a beacon signal.

32. The system of claim 30, wherein decoding each received signal further comprises associating a channel/color code detected from the received signal with a known combination of a particular antenna.

33. The system of claim 29, wherein identifying the originating antenna further comprises keying-up a test channel for propagating a signal into the collection location.

34. The system of claim 29, wherein collecting signal data throughout the sector further comprises conducting mobile data collection.

35. The system of claim 29, wherein normalized path loss is a function of distance of the collection location from the originating antenna and antenna characteristics.

36. The system of claim 29, wherein normalized path loss is a function of antenna characteristic.

37. The system of claim 36, wherein the antenna characteristic is defined by at least one of directional gain of antenna, location of antenna, RF mount, RF path, boresight, mechanical tilt and the electrical tilt of the antenna.

38. The system of claim 29, wherein collecting signal data further comprises tuning the RF scanner to a first frequency.

39. The system of claim 29, wherein the antenna directed away from the collection location includes an antenna located an adjacent sector and facing away from the collection location.

40. The system of claim 29, wherein the signal received from the antennas directed away from the collection location further comprises signals received at the collection location as backscatter or side scatter.

41. The system of claim 29, wherein each signal from each antenna is normalized independently.

42. An apparatus for determining signal strength at a location within a sector of a wireless communication system comprising:

an RF scanner;

a geo-location device, said geo-location device communicating with the RF scanner; and

a processor operationally connected to said RF scanner, the processor programmed with instructions to;

direct the RF scanner to measure signal strength of a plurality of incoming signals having a common frequency at a location, the signal strength including contribution from backscatter and antennas facing away from the location;

identify an originating antenna associated with each of the incoming signals;

determine a path loss value for the originating antenna;

normalize the path loss value for each antenna as a function of the originating antenna characteristic; and

determine signal strength as a function of combined signal strength from each of the plurality of incoming signals and normalized path loss value.

43. The apparatus of claim 42, wherein measuring signal strength further comprises decoding each received signal to identify the originating antenna.

44. The apparatus of claim 43, wherein decoding each received signal further comprises associating a channel/color code detected from the signal with a known combination of a particular antenna.

45. The apparatus of claim 42, wherein the incoming signal is a beacon signal.

46. The apparatus of claim 42, wherein identifying the originating antenna further comprises keying-up a test channel for propagating a signal into the collection location.

47. The apparatus of claim 42, wherein the processor is further programmed to determine signal strength at a plurality of collection locations throughout a sector to define a propagation model of the sector.

48. The apparatus of claim 47, wherein the plurality of collection locations define a test route.

49. The apparatus of claim 42, wherein the antenna characteristic is defined by at least one of directional gain of antenna, location of antenna, RF mount, RF path, boresight, mechanical tilt and the electrical tilt of the antenna.

50. The apparatus of claim 42, wherein the path loss is determined as a function of design, directionality and orientation of the antenna.

51. The apparatus of claim 42, wherein the processor is further programmed with instructions to establish a route through the sector for measuring signal strength.

52. The apparatus of claim 42, wherein the signal strength further comprises contribution from antenna sidescatter.

53. The apparatus of claim 42, wherein each signal from each antenna is normalized independently.