Systems and methods for microwave tomography

• US 8,526,341 B2
• Filed: 05/19/2008
• Issued: 09/03/2013
• Est. Priority Date: 05/17/2007
• Status: Active Grant

• Current Assignee: University of Iowa Research Foundation
• Original Assignee: University of Iowa Research Foundation
• Inventors: Cover, Mathew B., Andersen, David R.
• Primary Examiner(s): Mui, Gary
• Application Number:
  US12/123,346
• Publication Number:
  US 20090040952A1
• Time in Patent Office: 1,933 Days
• Field of Search: 370/310, 370/252, 370/253, 455/446, 455/456.5, 455/456.1, 367/7
• US Class Current: 370/310
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: H04W 84/10 Small scale networks; Flat hierarchical networks

Abstract

Systems and methods for microwave tomography are described. According to various embodiments, signal strength values or other similar quality indications may be analyzed as they are received with packet data over a wireless network. The analysis may be used to determine the presence of a physical object substantially between communicating nodes in the wireless network. An output may be generated based on analyzed data. Other embodiments are described and claimed.

Claims

1. A method comprising:

receiving a packet wirelessly transmitted within a wireless data network from a first node to a second node, the packet including non-payload data including signal strength information and source location information;

analyzing a signal strength value of the received packet and a relative location of the first node using the non-payload data;

performing a tomographic analysis based on the signal strength value and the relative location of the first node, the tomographic analysis creating a tomographic image;

determining whether a physical object is present at least partially between the first node and the second node such that the packet is transmitted through the physical object using the tomographic image; and

outputting data based on the determination of the presence of the physical object.

2. The method of claim 1, wherein the packet is transmitted using a spread spectrum transmission.

3. The method of claim 1, wherein the wireless data network is a personal area network (PAN).

4. The method of claim 1, wherein the signal strength value is a received signal strength indication (RSSI) value.

5. The method of claim 1, further comprising receiving one or more further packets and measuring signal strength values of the received one or more further packets transmitted within the wireless data network.

6. The method of claim 5, further comprising determining size characteristics of the physical object based on the signal strength values of the received packet and the received one or more further packets.

7. The method of claim 5, further comprising determining position characteristics of the physical object based on the signal strength values of the received packet and the received one or more further packets.

8. The method of claim 5, further comprising determining shape characteristics of the physical object based on the signal strength values of the received packet and the received one or more further packets.

9. A system for determining presence of a physical object in a wireless network, the system comprising:

a wireless device of the wireless network, the wireless device including;

a receiver configured to receive a packet transmitted from a transmitter of the wireless network over a wireless path being a straight-line path between the transmitter and the receiver in the wireless network; and

a packet analysis module configured to collect non-payload data from the received packet, the non-payload data including information on signal strength and relative location of the transmitter; and

an external device configured to communicate with the wireless device,

wherein one of the packet analysis module and the external device is configured to perform a tomographic analysis creating a tomographic image using the information on signal strength and relative location of the transmitter and determine the presence of the physical object along the wireless path using the tomographic image.

10. The system of claim 9, wherein the non-payload data includes link quality data.

11. The system of claim 9, wherein the packet analysis module is configured to communicate the non-payload data to the external processor, and the external processor is configured to determine the presence of the physical object along the wireless path using the information on signal strength and relative location of the transmitter by performing the tomographic analysis based on the non-payload data.

12. The system of claim 9, further comprising a transmitter configured to transmit a packet over a wireless path, the packet including an identification associated with the receiver, and signal strength data.

13. A system for determining presence of a physical object in a wireless network, the system comprising:

a first device of the wireless network, the first device configured to transmit a packet over a wireless medium, the packet including non-payload data including signal strength information and source location information indicative of location of the first device;

a second device of the wireless network, the second device configured to receive the packet; and

an analysis module in communication with the second device, the analysis module configured to perform a tomographic analysis creating a tomographic image using the non-payload data including the signal strength information and the source location information and determine presence of the physical object at least partially along a straight-line path between the first device and the second device using the tomographic image.

14. The system of claim 13, further comprising:

a third device configured to transmit a further packet over the wireless medium; and

a fourth device configured to receive the further packet, wherein the analysis module is in communication with the fourth device and configured to analyze non-payload data of the received further packet in the tomographic analysis to determine the location of the physical object within the wireless network.

15. A system for determining presence of a physical object in a wireless network, the system comprising:

a packet analysis module configured to interface with a wireless receiver of the wireless network and analyze non-payload information of packets received by the wireless receiver, the packets transmitted from a wireless transmitter of the wireless network to the wireless receiver through a straight-line path between the wireless transmitter and the wireless receiver, the non-payload information including signal strength information and source location information allowing for determination of a location of the wireless transmitter, the packet analysis module configured to output the analyzed non-payload information; and

a data analysis application configured to receive the analyzed non-payload information from the packet analysis module, perform a tomographic analysis creating a tomographic image using the analyzed non-payload information including the location of the wireless transmitter, and calculate physical characteristics of the physical object within a wireless network using the tomographic image, the physical object being substantially along the straight-line path between the wireless transmitter and the wireless receiver.

16. The system of claim 15, wherein the physical characteristics of the physical object include at least one of the following:

location, size, shape, reflectivity, and motion.

17. The system of claim 15, further comprising an interface displaying the location of the physical object within the wireless network.

18. The system of claim 15 further comprising at least one additional packet analysis module to interface with one or more additional wireless receivers to analyze non-payload information of additional packets received by the additional wireless receivers, and to output the non-payload information of the additional packets to the data analysis application.

19. The system of claim 15, wherein the data analysis application is physically separate from the packet analysis module.