Wireless sensor network access point and device RF spectrum analysis system and method

• US 8,737,244 B2
• Filed: 11/29/2010
• Issued: 05/27/2014
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Rotvold, Eric Darrell, Orth, Kelly Michael, Carlson, Daniel Clifford, Schnaare, Theodore Henry, Citrano, Joseph III
• Primary Examiner(s): HUYNH, KHOA B
• Application Number:
  US12/955,072
• Publication Number:
  US 20120134280A1
• Time in Patent Office: 1,275 Days
• Field of Search: None
• US Class Current: 370/252
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system for measuring and analyzing radio frequency power proximate and within a wireless field device mesh network. A centralized software module (CSWM) collects and analyzes values from one or more wireless devices of the wireless field device mesh network representing received RF power measurements on an assigned RF channel and values representing corresponding times of the received RF power measurements. Each wireless device measures received RF power on the assigned RF channel at times other than during reception of a signal resulting in transmission by the wireless device of either an acknowledgment signal or a non-acknowledgement signal. Values representing the received RF power measurements and the corresponding times of the received RF power measurements are determined from the stored received RF power measurements and corresponding times and then discarded. These values are stored within the wireless device until successfully reported. A network manager coordinates communication between the wireless devices and synchronizes the corresponding times of received RF power measurement throughout the wireless field device mesh network.

Claims

1. A method for measuring and analyzing radio frequency (RF) interference proximate and within a wireless field device network, the method comprising:

coordinating RF channel assignments and coordinating and synchronizing times of measurement;

wherein a network manager coordinates RF channel assignments and coordinates and synchronizes times of measurement throughout the wireless field device network;

measuring received RF power on an assigned RF channel with at least one of a plurality of wireless devices comprising the wireless field device network;

storing the measurement of received RF power measured on the assigned RF channel and a corresponding time of measurement within the at least one of the plurality of wireless devices if the measurement of RF power on the assigned RF channel was not during reception of a signal resulting in transmission by the at least one of the plurality of wireless devices of one of an acknowledgement signal and a non-acknowledgement signal;

determining within the at least one of the plurality of wireless devices values representing the received RF power measurements on the assigned RF channel and values representing the corresponding times of measurement from the stored measurements of RF power and the stored corresponding times of measurement;

discarding the measurements of received RF power and the corresponding times of measurement stored within the at least one of the plurality of wireless devices after determining the values representing the received RF power measurements on the assigned RF channel and values representing the corresponding times of measurement from the stored measurements of received RF power and the stored corresponding times of measurement;

reporting from the at least one of the plurality of wireless devices the values representing the received RF power measurements on the assigned RF channel and the values representing the corresponding times of measurement to a centralized software module (CSWM);

receiving at the at least one of the plurality of wireless devices a signal acknowledging successful reporting of the values representing the received RF power measurements on the assigned RF channel and the values representing the corresponding times of measurement; and

discarding the values representing the received RF power measurements on the assigned RF channel and the values representing the corresponding times of measurement within the at least one of the plurality of wireless devices upon receipt of the signal acknowledging successful reporting of the values representing the received RF power measurements on the assigned RF channel and the values representing the corresponding times of measurement.

2. The method of claim 1, further comprising running the CSWM and the network manager each on at least one of a gateway and a host computer.

3. The method of claim 1, wherein reporting the values representing the received RF power measurements on the assigned RF channel and the corresponding times of measurement to the CSWM comprises transmitting a report through the wireless field device network in a staggered fashion.

4. The method of claim 1, wherein reporting the values representing the received RF power measurements on the assigned RF channel and corresponding times of measurement to the CSWM occurs at a rate configurable by the network manager.

5. The method of claim 1, wherein the corresponding time of measurement is during a portion of a time slot when communication on the assigned RF channel is scheduled and the at least one of the plurality of wireless devices does not transmit an acknowledgement signal or a non-acknowledgement signal during the time slot.

6. The method of claim 1, wherein the corresponding time of measurement is during a time slot when no communication on the assigned RF channel is scheduled throughout the wireless field device network.

7. The method of claim 1, wherein the corresponding time of measurement is during a portion of a time slot when no communication on any RF channel is scheduled for the portion of the time slot throughout the wireless field device network.

8. The method of claim 1, wherein the signal acknowledging successful reporting of the values representing the received RF power measurements on the assigned RF channel and the values representing the corresponding times of measurement originates from at least one of a neighboring node and the CSWM.

9. The method of claim 1, further comprising displaying the values representing the received RF power measurements of the assigned RF channel on a multipoint gradient map.

10. The method of claim 1, further comprising displaying on a local operator interface at least one of:

measurements of received RF power measured on the assigned RF channel and the corresponding time of measurement; and

values representing the received RF power measurements on the assigned RF channel.

11. The method of claim 1, further comprising:

monitoring at the CSWM the reported values representing the received RF power measurements and the values representing the corresponding times of measurement on the assigned RF channel;

detecting RF interference when at least one of the monitored values representing the received RF power measurements exceeds a predetermined value; and

generating an alert from the CSWM notifying at least one of a system operator and a control or monitoring software application running on a host computer of the RF interference.

12. The method of claim 11, further comprising:

analyzing at the CSWM the reported values representing the received RF power measurements and the values representing the corresponding times of measurement on the assigned RF channel of the detected RF interference;

creating an RF spectrum signature at the CSWM for the RF interference from the analyzed values;

comparing the RF spectrum signature for the of RF interference with a plurality of RF spectrum signatures at the CSWM, each of the plurality of RF spectrum signatures identifying a known source of RF interference;

identifying the source of RF interference from the compared RF spectrum signatures.

13. The method of claim 11, further comprising:

analyzing at the CSWM the reported values representing the received RF power measurements and the values representing the corresponding times of measurement on the assigned RF channel of the detected RF interference;

determining a temporal pattern for the RF interference from the analyzed values at the CSWM;

comparing the temporal pattern for the of RF interference with a plurality of RF temporal patterns at the CSWM, each of the plurality of RF temporal patterns identifying a known source of RF interference;

identifying the source of RF interference from the compared RF temporal patterns.

14. The method of claim 1, wherein determining values representing the received RF power measurements on the assigned RF channel comprises calculating statistical values within the at least one of the plurality of wireless devices of the stored measurements of received RF power and the stored corresponding times of measurement, wherein calculating statistical values comprises calculating at least one of maximum, minimum, average, standard deviation and variance values of the stored measurements of received RF power.

15. The method of claim 14, further comprising:

comparing at the CSWM the calculated statistical values and the corresponding times of measurement for the assigned RF channel from at least two of the plurality of wireless devices, wherein at least two of the plurality of wireless devices are at locations known to the CSWM;

determining two possible locations of a source of RF interference on the assigned RF channel at the CSWM from the compared calculated statistical values and times and from the known locations of the at least two of the plurality of wireless devices;

comparing non-RF interference characteristics of the two possible locations of the source of RF interference on the assigned RF channel at the CSWM to determine a location of the source of RF interference; and

reporting the location of the source of the RF interference to at least one of a system operator and a control or monitoring software application running on a host computer.

16. The method of claim 14, further comprising:

comparing at the CSWM the calculated statistical values and the corresponding times of measurement for the assigned RF channel from at least three of the plurality of wireless devices, wherein at least three of the plurality of wireless devices are at locations known to the CSWM;

determining a location of a source of RF interference on the assigned RF channel at the CSWM from the compared calculated statistical values and times and from the known locations of the at least three of the plurality of wireless devices; and

reporting the location of the source of the RF interference to at least one of a system operator and a control or monitoring software application running on a host computer.

17. The method of claim 16, wherein the locations of the at least three of the plurality of wireless devices are fixed locations.

18. A system for measuring and analyzing radio frequency (RF) interference proximate and within a wireless field device network, the system comprising:

a centralized software module (CSWM) for collecting and analyzing values representing received RF power measurements on an assigned RF channel and values representing corresponding times of the received RF power measurements;

a plurality of wireless devices, each wireless device measuring received RF power and a corresponding time of measurement on the assigned RF channel;

storing the measurement of received RF power if the measurement is not during reception of a signal resulting in transmission by the wireless device of one of an acknowledgement signal and a non-acknowledgement signal;

employing the stored received RF power measurement and the corresponding time of measurement to determine the values representing the received RF power measurements and the values representing the corresponding times of measurement for the assigned RF channel;

wherein the stored received RF power measurement and the corresponding time of measurement are stored in the wireless device until the values representing the received RF power measurements and the values representing the corresponding times of measurement for the assigned RF channel are determined;

wherein the values representing the received RF power measurements and the values representing the corresponding times of measurement are stored in the wireless device until receipt of a signal acknowledging successful reporting of the values representing received RF power measurements on the assigned RF channel and values representing corresponding times of the received RF power measurements from the wireless device; and

a network manager for coordinating communications between the plurality of wireless devices, coordinating RF channel assignments, and coordinating and synchronizing the corresponding times of measurement throughout the wireless field device network.

19. The system of claim 18, wherein each wireless device stores the measurement of received RF power if the measurement is within a defined range of RF power measurements.

20. The system of claim 18, wherein each wireless device provides the values representing received RF power measurements and the values representing corresponding times of measurement and the assigned RF channel to the CSWM as by transmitting a report through the wireless field device network in a staggered fashion coordinated by the network manager.

21. The system of claim 18, wherein each wireless device provides the values representing received RF power measurements and the values representing corresponding times of measurement and the assigned RF channel to the CSWM at a rate configurable by the network manager.

22. The system of claim 18, wherein each wireless device stores the measurement of received RF power if the measurement is during a portion of a time slot when communication on the assigned RF channel is scheduled and the wireless device does not transmit an acknowledgement signal or a non-acknowledgement signal during the time slot.

23. The system of claim 18, wherein each wireless device stores the measurement of received RF power if the measurement is during a time slot when no communication on the assigned RF channel is scheduled throughout the wireless field device network.

24. The system of claim 18, wherein each wireless device stores the measurement of received RF power if the measurement is during a portion of a time slot, wherein no communication on any RF channel is scheduled for the portion of the time slot throughout the wireless field device network.

25. The system of claim 18, wherein the network manager coordinates the corresponding times of measurement throughout the wireless field device network such that the corresponding times of measurement are during at least one of:

a portion of a first time slot when communication on the assigned RF channel is scheduled and the wireless device does not transmit an acknowledgement signal or a non-acknowledgement signal during the first time slot;

a second time slot when no communication on the assigned RF channel is scheduled throughout the wireless field device network; and

a portion of a third time slot, wherein no communication on any RF channel is scheduled for the portion of the third time slot throughout the wireless field device network.

26. The system of claim 18, wherein the network manager coordinates the corresponding times of measurement throughout the wireless field device network such that the corresponding times of measurement are during at least one of:

a first portion of a first time slot, wherein no communication on any RF channel is scheduled for the first portion of the first time slot throughout the wireless field device network;

a second portion of the first time slot when communication on the assigned RF channel is scheduled and the wireless device does not transmit an acknowledgement signal or a non-acknowledgement signal during the first time slot; and

a second time slot when no communication on the assigned RF channel is scheduled throughout the wireless field device network.

27. The system of claim 18, wherein the signal acknowledging successful reporting of the values representing received RF power measurements on the assigned RF channel and values representing corresponding times of the received RF power measurements from the wireless device originates from at least one of a neighboring node and the CSWM.

28. The system of claim 18, wherein at least one of the plurality of wireless devices further comprises a local operator interface, the local operator interface capable of displaying at least one of:

measurements of received RF power measured on the assigned RF channel and the corresponding time of measurement; and

values representing the received RF power measurements on the assigned RF channel.

29. The system of claim 18, further comprising a hand-held wireless device, the hand-held wireless device measuring received RF power and a corresponding time of measurement on a user-selected RF channel if the measurement of RF power on the selected RF channel is not during reception of a signal resulting in transmission by the hand-held wireless device of one of an acknowledgement signal and a non-acknowledgement signal;

wherein the network manager coordinates communications between the plurality of wireless devices and the hand-held wireless device and coordinates and synchronizes the corresponding times of measurement for the hand-held wireless device.

30. The system of claim 18, wherein the CSWM and the network manager are each running on at least one of a gateway and a host computer.

31. The system of claim 30, wherein the CSWM directs at least one of the gateway or the host computer to display the values representing the received RF power measurements on the assigned RF channel on a multipoint gradient map.

32. The system of claim 18, wherein the CSWM:

monitors the values representing received RF power measurements on the assigned RF channel;

detects RF interference when at least one of the monitored values exceeds a predetermined value; and

generates an alert notifying at least one of a system operator and a control or monitoring software application running on a host computer of the RF interference.

33. The system of claim 32, wherein the CSWM further:

analyzes the values representing received RF power measurements on the assigned RF channel for the detected RF interference;

creates an RF spectrum signature for the RF interference from the analyzed values;

compares the RF spectrum signature with a plurality of RF spectrum signatures, each of the plurality of RF spectrum signatures identifying a known source of RF interference, and

identifies the source of RF interference from the compared RF spectrum signatures.

34. The system of claim 32, wherein the CSWM further:

analyzes the values representing received RF power measurements and the values representing corresponding times of measurement on the assigned RF channel for the detected RF interference;

determines a temporal pattern for the RF interference from the analyzed values;

compares the temporal pattern for the RF interference with a plurality of RF temporal patterns, each of the plurality of RF temporal patterns identifying a known source of RF interference, and

identifies the source of RF interference from the compared RF temporal patterns.

35. The system of claim 18, wherein the values representing received RF power measurements determined by each wireless device are statistical values for the assigned RF channel, wherein the statistical values comprise at least one of maximum, minimum, average, standard deviation, and variance values.

36. The system of claim 35, wherein the CSWM:

compares the statistical values and the corresponding times of measurement for the assigned RF channel from at least two of the plurality of wireless devices, wherein at least two of the plurality of wireless devices are at locations known to the CSWM;

determines two possible locations of a source of RF interference on the assigned RF channel from the compared statistical values and times and from the known locations of the at least two of the plurality of wireless devices;

compares non-RF interference characteristics of the two possible locations of the source of RF interference on the assigned RF channel to determine a location of the source of RF interference; and

reports the location of the source of the RF interference to at least one of a system operator and a control or monitoring software application running on a host computer.

37. The system of claim 35, wherein the CSWM:

compares the statistical values and the corresponding times of measurement for the assigned RF channel from at least three of the plurality of wireless devices, wherein at least three of the plurality of wireless devices are at locations known to the CSWM;

determines a location of a source of RF interference on the assigned RF channel from the compared statistical values and times and from the known locations of the at least three of the plurality of wireless devices; and

reports the location of the source of the RF interference to at least one of a system operator and a control or monitoring software application running on a host computer.

38. The system of claim 37, wherein the locations of the at least three of the plurality of wireless devices known to the CSWM are fixed locations.