Wireless node location mechanism featuring definition of search region to optimize location computation
First Claim
1. A method for estimating the location of a wireless node relative to a plurality of radio receivers operative to detect the strength of RF signals, wherein a RF coverage map, corresponding to each of the radio receivers, characterizes the signal strength values for locations in a physical region out to a threshold signal strength level, comprising collecting signal strength values, detected at a plurality of radio receivers, corresponding to signals transmitted by a wireless node;
- defining a search region based on the intersection of the RF coverage maps corresponding to radio receivers that detected signals transmitted by the wireless node;
computing, within the defined search region, the estimated location of the wireless node based on the collected signal strength values and the RF coverage maps corresponding to the plurality of radio receivers.
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Abstract
A wireless node location mechanism that defines a search region to optimize the computations associated with estimating the location of a given wireless node. According to one implementation, a coverage map associated with each radio receiver that records signal strength data is defined out to a threshold signal strength level. Before computing the estimated location of a given wireless nodes, a search region is defined based on the intersection of the coverage maps associated with each radio receiver that detects the wireless node. Some implementations use information provided by the fact that certain radio receivers did not detect the wireless node to further optimize the location estimate. By defining a search region, which is a generally small area relative to the space encompassed by an entire RF environment, the present invention provides several advantages, such as reducing the processing time and/or power to compute estimated locations for wireless nodes.
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Citations
33 Claims
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1. A method for estimating the location of a wireless node relative to a plurality of radio receivers operative to detect the strength of RF signals, wherein a RF coverage map, corresponding to each of the radio receivers, characterizes the signal strength values for locations in a physical region out to a threshold signal strength level, comprising
collecting signal strength values, detected at a plurality of radio receivers, corresponding to signals transmitted by a wireless node; -
defining a search region based on the intersection of the RF coverage maps corresponding to radio receivers that detected signals transmitted by the wireless node;
computing, within the defined search region, the estimated location of the wireless node based on the collected signal strength values and the RF coverage maps corresponding to the plurality of radio receivers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus facilitating the location of a wireless node in a RF environment, comprising
a plurality of radio receivers comprising at least one antenna, the plurality of radio receivers operative to detect the strength of signals transmitted by wireless nodes and provide the detected signal strengths to a wireless node location model; - wherein a RF coverage map, corresponding to each of the radio receivers, characterizes the signal strength values for locations in a physical region out to a threshold signal strength level, and
a wireless node location module operative to define a search region based on the intersection of the RF coverage maps corresponding to radio receivers that detected signals transmitted by the wireless node; and
compute within the search region the estimated location of the wireless node based on the collected signal strength values and the RF coverage maps corresponding to the plurality of radio receivers.
- wherein a RF coverage map, corresponding to each of the radio receivers, characterizes the signal strength values for locations in a physical region out to a threshold signal strength level, and
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17. A method for estimating the location of a wireless node relative to a plurality of radio receivers operative to detect the strength of RF signals, wherein a RF coverage map, corresponding to each of the radio receivers, characterizes the signal strength values for locations in a physical region out to a threshold signal strength value, comprising
collecting signal strength values, detected at a plurality of radio receivers, corresponding to signals transmitted by a wireless node; -
defining a search region based on the intersection of the RF coverage maps corresponding to radio receivers that detected signals transmitted by the wireless node; and
computing within the search region the estimated location of the wireless node by comparing, for all unique pairs of radio receivers, the differences in the signal strength values detected by the plurality of radio receivers to corresponding differences in the signal strength values in the RF coverage maps associated with the plurality of radio receivers, wherein the comparison is weighted as a function of at least one of the signal strength values detected by each unique pair of radio receivers. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 28)
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29. In a wireless network environment comprising a plurality of radio receivers deployed within a physical space, a method facilitating location of wireless nodes, the method comprising
defining a location-coordinate model of a physical space, wherein the model includes the locations of a plurality of radio receivers; -
determining coverage maps for each of the plurality of radio receivers, wherein the coverage map, for a given radio receiver, defines the expected receive signal strength for locations in the physical space proximal to the given radio receiver;
wherein the boundary of the coverage map is rectangular and defined at least in part by a minimum threshold receive signal strength level;
storing the coverage maps as individual entities in a database. - View Dependent Claims (30, 31, 32, 33)
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Specification