Patent Description:
In its first iterations, the IEEE <NUM>. 11a/b standards specified transfer rates of up to <NUM> Mbps at a range of up to <NUM> feet. The IEEE <NUM> amendment implemented various improvements, including Orthogonal Frequency Division Multiplexing ("OFDM"), to increase transfer rates to up to <NUM> Mbps while maintaining backward compatibility with IEEE <NUM>. The IEEE <NUM>. 11n amendment added Multiple Input Multiple Output ("MIMO") functionality where multiple transmitters and receivers operate simultaneously at one or both ends of the link to facilitate transfer rates of up to <NUM> Mbps and even higher if additional antennae are used. The IEEE <NUM>. 11ac amendment added support for spatial streams and increased channel widths to substantially increase transfer rates from <NUM> Mbps to several Gbps and works exclusively in the less crowded <NUM> frequency band and at a range of up to <NUM> feet or more.

The IEEE <NUM> standard remains an evolving technical standard and future amendments will likely seek to increase transfer rates, improve connectivity in challenging environments, and enhance security. As such, Wi-Fi remains the most widely adopted wireless networking standard in the world and will likely remain so for the foreseeable future.

<CIT> describes a system and method for transmitting occupancy-related data from sensors to a remote server using smart phones instead of a gateway. Sensors in a building or other location collect and buffer occupancy-related data. Each sensor periodically generates an advertisement beacon with an identifier and a data payload that includes buffered occupancy-related data. The sensors wirelessly broadcast the advertisement beacons. A plurality of mobile devices (e.g., smartphones) execute an application that scans for advertisement beacons with the above-referenced identifier. In response to a mobile device with the application being in the vicinity of a sensor and detecting an advertisement beacon with the identifier, the mobile device forwards the advertisement beacon to a remote server, which uses the beacon's data payload to calculate the occupancy of a building or location.

<CIT> describes a asset tag apparatus and method of monitoring assets uses a wireless communication protocol to generate and transmit output values of sensors coupled to a beacon within a transmission range to a computing device. The advertising message of the wireless communication protocol is transmitted when a sensor output exceeds a threshold or on periodic time basis. Historic sensor data occurring at consecutive sensor threshold exceeding events is interleaved with live sensor output data in consecutive advertising packets.

<CIT> describes a system of saving battery power in a battery powered Wi-Fi device. The system includes a battery powered Wi-Fi device configured to transmit a customized beacon frame from the battery powered Wi-Fi device to a Wi-Fi enabled device. The customized beacon frame includes battery status information. In another form, a method of saving battery power in a battery powered Wi-Fi device. The method includes transmitting a customized beacon frame from the battery powered Wi-Fi device to a Wi-Fi enabled device. The customized beacon frame includes battery status information. In another form, a system for saving sensor battery power includes a battery powered sensor configured to transmit a customized beacon frame from the battery powered sensor to a Wi-Fi enabled device. The customized beacon frame includes sensor data. Customized beacon frame may be sent from the Wi-Fi enabled device to a wireless network.

The Invention is set out in the appended set of claims.

Other aspects of the present invention will be apparent from the following description and claims.

One or more embodiments of the present invention are described in detail with reference to the accompanying figures. For consistency, like elements in the various figures are denoted by like reference numerals. In the following detailed description of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known features to one of ordinary skill in the art are not described to avoid obscuring the description of the present invention.

Conventional asset tracking systems use dedicated and complicated hardware and software systems to track physical assets, typically within the confines of a fixed location or from portal-to-portal of one or more fixed locations. Conventional asset tracking systems typically use, for example, barcode, Near-Field Communication ("NFC"), Bluetooth Low Energy ("BLE"), Radio-Frequency Identification ("RFID") tags, and Global Positioning System ("GPS") to tag and affirmatively track assets within their respective asset tracking system. In typical applications, the asset tracking task is knowingly and actively performed by dedicated hardware and software systems intentionally deployed for the asset tracking task. As such, an inherent limitation in conventional asset tracking systems is the requirement that the tagging, tracking, hardware, and software systems must be intentionally deployed, span the zone of coverage, and knowingly and actively perform and manage the asset tracking task. This requires extensive investment in expensive hardware and software systems and in hiring and training personnel on its usage. Moreover, in a widespread deployment of assets across many sites, perhaps even around the world, it is exceptionally difficult and cost prohibitive to deploy and manage a coherent conventional asset tracking system.

Accordingly, in one or more embodiments of the present invention, a method and system of passive asset tracking with existing infrastructure allows for passively tracking moveable assets by one or more wireless devices that happen to come in-range of Wi-Fi access point signals even though the wireless device, or user thereof, may not even know they are participating in the asset tracking task. In this way, the community of smartphones that happen to be in the vicinity of an asset that is desired to be tracked may, anonymously, and without awareness, participate in the asset tracking task. By using this existing infrastructure, moveable assets may be passively tracked by one or more unrelated wireless devices whenever the one or more of the wireless devices merely come into range of one or more assets associated with a Wi-Fi access point broadcasting Wi-Fi signals, without any intent or awareness on the part of the wireless device, or user thereof, that they are participating in the asset tracking task due to the nature of the Wi-Fi wireless network discovery protocol. In addition, the method and system leverage existing infrastructure inherent in smartphones and smartphone operating systems to report their location, as well as the unique identifying information of Wi-Fi access points they encounter, typically for improving the accuracy of location-based services. Advantageously, the Wi-Fi wireless network discovery protocol as well as the Wi-Fi access point reporting feature of smartphones may be cooperatively used to passively track assets associated with Wi-Fi access points by one or more wireless devices without requiring that the wireless devices authenticate to, or associate with, any particular Wi-Fi access point, using publicly accessibly Wi-Fi signals, and in passive scanning applications, completely anonymously with respect to the asset tracking task.

<FIG> shows a conventional Wi-Fi wireless network <NUM>. A conventional Wi-Fi wireless network <NUM> typically includes a broadband modem <NUM> that provides high-speed Internet connectivity to one or more wireless devices (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) via a Wi-Fi access point <NUM>. Wi-Fi access point <NUM> typically facilitates wireless connectivity between one or more of the wireless devices and, in configurations that include an integrated router, may serve as the bridge between the wireless devices (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) and an upstream network connection, such as, for example, the Internet connection, provided by broadband modem <NUM>. In conventional use, a wireless connection may be established between one or more wireless devices (e.g., <NUM>, <NUM>, <NUM>, and <NUM>), including, for example, a television <NUM>, computer <NUM>, tablet computer <NUM>, smartphone <NUM>, or any other wireless device, and Wi-Fi access point <NUM>, thereby allowing the wireless devices (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) to communicate with one another and access the Internet via broadband modem <NUM>. Wi-Fi access points <NUM> are commonly found in homes, offices, and public places, where they are often referred to as Wi-Fi hotspots. While the number of Wi-Fi access points <NUM> has not been definitively counted, there are believed to be in excess of one billion Wi-Fi access points <NUM> around the world. Efforts to map Wi-Fi signal coverage suggest that most modern cities are blanketed with publicly accessible Wi-Fi signals. Notwithstanding the above, one of ordinary skill in the art will recognize that a conventional Wi-Fi network <NUM> does not require a broadband modem <NUM> or Internet connectivity and may be used as a purely wireless network to facilitate wireless communications between one or more wireless devices (e.g., <NUM>, <NUM>, <NUM>, and <NUM>).

<FIG> shows passive scanning mode <NUM> as part of Wi-Fi wireless network discovery. Wi-Fi wireless network discovery is the process by which a wireless device identifies and potentially authenticates to, and associates with, an in-range Wi-Fi access point <NUM>. In passive scanning mode, one or more wireless devices <NUM> listen for beacon frames broadcast <NUM> at periodic intervals by one or more in-range Wi-Fi access points <NUM> to announce the presence of their respective wireless networks. Beacon frames are a type of management frame that includes information regarding the broadcasting Wi-Fi access point <NUM> to facilitate potential authentication, association, and connectivity. Each beacon frame includes a Service Set Identifier ("SSID"), which is typically a user-given name for the broadcasting Wi-Fi wireless network, and information that uniquely identifies the Wi-Fi access point <NUM> including, but not limited to, a Basic Service Set Identifier ("BSSID"), which is a unique Media Access Control ("MAC") address of the Wi-Fi access point <NUM> or a broadcasting band thereof. Multiple Wi-Fi access points <NUM> may share the same SSID as part of the same wireless network, but each Wi-Fi access point <NUM> will have a unique BSSID. Moreover, dual or multi-band Wi-Fi access points <NUM> that broadcast on multiple frequency bands, typically have a unique BSSID for each frequency band that they broadcast on.

A wireless device (e.g., smartphone <NUM>) may be statically or transiently located within the broadcast range of one or more Wi-Fi access points (e.g., 110a, 110b, and 110c). Each Wi-Fi access point <NUM> may periodically broadcast their beacon frame (e.g., 210a, 210b, and 210c) announcing the presence of their respective Wi-Fi wireless network. Wireless device <NUM> may listen to, and receive, beacon frames from the in-range Wi-Fi access points (e.g., 110a, 110b, and 110c). In conventional applications, a user of wireless device <NUM> may optionally select, on their device, the SSID of the Wi-Fi access point, i.e., 110a, of the Wi-Fi wireless network that they wish to join and then communicate <NUM> with the Wi-Fi access point 110a to establish wireless connectivity. It is important to note that, passive scanning <NUM> is completely anonymous with respect to wireless devices <NUM> that receive the beacon frames of in-range Wi-Fi access points <NUM> until such time that they choose to authenticate to, and associate with, a particular Wi-Fi access point <NUM>. Unless and until a user of a wireless device <NUM> selects a specific Wi-Fi access point <NUM> and network thereof to authenticate to, and associate with, wireless device <NUM> may passively receive the Wi-Fi signals being publicly broadcast and remain completely anonymous.

<FIG> shows active scanning mode <NUM> as part of Wi-Fi wireless network discovery. In contrast to passive scanning mode, active scanning is a type of Wi-Fi wireless network discovery process where a wireless device <NUM> broadcasts a probe request frame <NUM> to a specific (not shown) or all Wi-Fi access points (e.g., 110a, 110b, and 110c) that are within range. A probe request frame is a type of management frame that may include information about the specific Wi-Fi access point (e.g., 110a) that the wireless device <NUM> wishes to authenticate to, and associate with, sometimes referred to as a directed probe request, or may be directed to all available Wi-Fi access points <NUM> within range, sometimes referred to as a null probe request. Responding in-range Wi-Fi access points 110a, 110b, and 110c transmit a probe response frame 320a, 320b, and 320c that includes information substantially similar to a beacon frame including their respective SSID and unique BSSID.

In contrast to passive scanning (e.g., <NUM>) where each Wi-Fi access point <NUM> broadcasts its respective beacon frames on a specific channel, in active scanning (e.g., <NUM>), wireless device <NUM> may broadcast probe request frames <NUM> across all available channels for the associated frequency band. In this way, wireless device <NUM> may, for example, select a Wi-Fi access point <NUM> that provides the strongest signal strength and quality. Moreover, even when a particular wireless device <NUM> is authenticated to, and associated with, a specific Wi-Fi access point (e.g., 110a), wireless device <NUM> may go off channel and continue to send probe request frames <NUM> on other channels. By continuing to actively probe for Wi-Fi access points <NUM>, wireless device <NUM> may maintain a list of known Wi-Fi access points <NUM> that may facilitate roaming should the wireless device <NUM> move out of range of the currently associated Wi-Fi access point <NUM>. In contrast to passive scanning (e.g., <NUM>), active scanning operations <NUM> only require a wireless device <NUM> to send a probe request on a specific channel within the designated frequency band and then listen for a comparatively smaller amount of time as compared to passive scanning (e.g., <NUM>). As such, active scanning <NUM> presents a more directed approach to wireless network discovery as compared to passive scanning operations (e.g., <NUM>).

<FIG> shows how various wireless networking technologies may be used to determine a location of a wireless device <NUM> and one or more Wi-Fi access points <NUM>. Wireless device <NUM>, which may be a smartphone as depicted or any other type or kind of wireless device, may establish a cellular connection with one or more cell towers <NUM> providing cellular network connectivity. An established connection to a particular cell tower <NUM> may, in some circumstances, be used to establish a location of wireless device <NUM> within a determinable radius of the particular cellular tower <NUM>. Further, patterns of connectivity to one or more cell towers <NUM> may be used to establish a location, or potentially even the movement, of wireless device <NUM> within a determinable radius. However, these techniques are rarely used outside of law enforcement.

Instead, wireless devices <NUM> typically rely on GPS signals to determine their location. Most wireless devices <NUM> include a GPS receiver (not independently shown) capable of receiving one or more GPS signals (not shown) from one or more GPS satellites (e.g., 420a, 420b, and 420c) in Earth orbit. Typically, there are at least four GPS satellites <NUM> visible to a wireless device <NUM> no matter where it is located, anywhere around the globe. Each GPS satellite <NUM> transmits a GPS signal (not shown) that includes information about the satellite's current position and the current time at regular intervals. The GPS receiver of wireless device <NUM> receives one or more of these GPS signals and calculates how far away it is from each satellite based on how long it took for each respective GPS signal to arrive. If the wireless device <NUM> receives the GPS signal from at least three GPS satellites <NUM>, the location of the wireless device <NUM> may be determined with a high degree of accuracy by a process referred to as trilateration. The GPS derived location of wireless device <NUM> may be determined continuously, periodically, or upon the execution of software that requires location services, such as, for example, navigation software or a web browser used to search nearby places. The accuracy of GPS is within a radius of approximately <NUM> feet under open skies and good conditions but worsens near structures and obstructions.

As such, a wireless device <NUM> may use one or more in-range Wi-Fi access points (e.g., 110a, 110b, or 110c) to improve the accuracy of the GPS location determination and, in instances when GPS is not available, determine its location based on Wi-Fi alone. As part of the Wi-Fi wireless network discovery process, wireless device <NUM> typically determines the signal strength of the Wi-Fi signals broadcast by the in-range Wi-Fi access points (e.g., 110a, 110b, or 110c). Assuming, for the purpose of this discussion, that the location of one or more Wi-Fi access points (e.g., 110a, 110b, or 110c) are already known to a certain degree of accuracy, the signal strengths may be used to refine the accuracy of the GPS location determination and, in instances when GPS is not available, determine the location of the wireless device <NUM> based on Wi-Fi alone. For example, the known location of a Wi-Fi access point (e.g., 110a) and the signal strength of the Wi-Fi signal received from it may be used in conjunction with the signal strength and known location of other Wi-Fi access points (e.g., 110b and 110c) to refine or determine the location of wireless device <NUM> by a process referred to as triangulation. It is important to note that the signal strength of the Wi-Fi signals received by wireless device <NUM> from one or more Wi-Fi access points <NUM> are determined without requiring wireless device <NUM> to authenticate to, or associate with, or otherwise join any particular Wi-Fi access point (e.g., 110a, 110b, or 110c). As such, wireless device <NUM> may use publicly broadcast Wi-Fi signals of in-range Wi-Fi access points <NUM> that it does not use or otherwise associate with in any way.

Above, an assumption was made that the location of one or more Wi-Fi access points <NUM> were known to a certain degree of accuracy. This assumption holds true because wireless devices <NUM> report in-range Wi-Fi access points <NUM> they encounter as well as their current location to the original equipment manufacturer, operating system developer, or other third-party who maintain a database, sometimes referred to herein as a Wi-Fi AP Database, typically to improve the accuracy of location determination as well as other location-related services (i.e., significant locations, location-based suggestions, location-based alerts, popular near me, and the like). While this benefits the user of wireless device <NUM> in providing improved services, each wireless device <NUM> discovers the existence, and reports the location, of Wi-Fi access points <NUM> it encounters on an ongoing continuous basis, typically without awareness on the part of the user. This is commonly performed as part of, for example, iOS® and Android® location services and it is generally available to third-party software developers for their use. In addition, many public and private companies maintain a centralized database that contains the identifying information and location of known Wi-Fi access points <NUM>. It is important to note that this information stored in such databases is typically obtained anonymously through publicly accessible Wi-Fi access point signals and in accordance with the terms and conditions of use of most smartphones, that typically provide the user with the option of opting-out of participation in such services.

<FIG> shows a block diagram of a conventional Wi-Fi access point <NUM>. A conventional Wi-Fi access point <NUM> includes a printed circuit board and related components (not shown) disposed within a casing or enclosure <NUM>, which may be integrated into other devices or equipment depending on the application or design. Wi-Fi access point <NUM> typically includes one or more antennae <NUM> for transmitting and receiving radio frequency Wi-Fi signals, and a power source <NUM>. In conventional applications, power source <NUM> is traditionally a DC power input, however, some industrial and commercial applications may use AC power input, and still other applications may use battery-powered power input. Wi-Fi access point <NUM> may or may not include an integrated router (not shown) and the associated connectivity. As such, in certain embodiments, Wi-Fi access point <NUM> may consist of a pure wireless access point that does not include a router and does not provide any bridge functionality to reduce the size, complexity, and power consumption of the device. In other embodiments, Wi-Fi access point (e.g., <NUM> of <FIG>) may not even function as an access point, but spoof aspects of the Wi-Fi wireless network discovery protocol, transmitting beacon frames, probe response frames, or other management frames as if it was a functional Wi-Fi access point <NUM>. Notwithstanding the above, one of ordinary skill in the art will recognize that any Wi-Fi access point <NUM>, dummy Wi-Fi access point (e.g., <NUM> of <FIG>), or other device capable of participating in the Wi-Fi wireless network discovery protocol as if it were a bona fide Wi-Fi access point <NUM> may be used in accordance with one or more embodiments of the present invention.

<FIG> shows an exemplary application of passive asset tracking with existing infrastructure <NUM> in accordance with one or more embodiments of the present invention. Specifically, in one or more embodiments of the present invention, one or more assets may be passively tracked by one or more wireless devices <NUM>, or Wi-Fi clients, that are in-range, or even come in and go out of range, of assets that broadcast Wi-Fi signals even though a wireless device <NUM>, or user thereof, may not even know that they are participating in the asset tracking task. As such, for the purpose of this disclosure, passive asset tracking means tracking an asset indirectly without requiring any particular wireless device <NUM> to authenticate to, or associate with, any particular Wi-Fi access point <NUM> or dummy version of Wi-Fi access point <NUM>. Accordingly, in certain embodiments, assets may be passively tracked by one or more wireless devices <NUM> that merely happen to come in-range of one or more assets broadcasting Wi-Fi access point signals even though a wireless device <NUM>, or user thereof, may or may not be aware that they are taking part in the asset tracking task. In other embodiments, one or more wireless devices <NUM> may passively track assets in a purposeful manner, whereby a wireless device <NUM> intentionally interacts with one or more Wi-Fi access points <NUM> or dummy Wi-Fi access points <NUM> associated with assets deployed in the field <NUM>. In all such embodiments, the Wi-Fi wireless network discovery process may be advantageously used by one or more wireless devices <NUM> to passively track assets without requiring that they authenticate to, associate with, or join any particular Wi-Fi access point <NUM> or dummy Wi-Fi access point <NUM>, using publicly accessible Wi-Fi signals, and in passive scanning applications, anonymously with respect to the asset tracking task.

Returning to the figure, in one or more embodiments of the present invention, one or more Wi-Fi access points (e.g., 110a/1700a, 110b/1700b, 110c/1700c, and 110d/ 1700d) may be disposed, or otherwise attached to, or even integrated with, one or more moveable assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) that may be deployed in the field <NUM>. For the purpose of illustration only, construction equipment (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) is shown in the figure as exemplars of moveable assets to be tracked. However, one of ordinary skill in the art will recognize that any asset may be tracked in accordance with one or more embodiments of the present invention. The Wi-Fi access points <NUM>/<NUM> are not required to authenticate to, associate with, or otherwise join any particular wireless network or any wireless network at all, as the Wi-Fi access points <NUM>/<NUM> may be used for the sole purpose of uniquely identifying an asset that is desired to be tracked. Specifically, each Wi-Fi access point <NUM>/<NUM> disposed on, or otherwise attached to, or even integrated with, an asset (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) may broadcast beacon frames (not shown) in passive scanning mode and/or respond to probe request frames (not shown) as part of active scanning mode, where either the beacon frame (not shown) or probe response frame (not shown) includes information that uniquely identifies the Wi-Fi access point/dummy Wi-Fi access point <NUM>/<NUM>, and, to those who recognize the association by proxy with a particular asset (e.g., <NUM>, <NUM>, <NUM>, and <NUM>), the asset itself. One of ordinary skill in the art will recognize that the beacon frame, probe response frame, or other management frame may contain other information that may be customized or helpful to the asset tracking task.

In certain embodiments, in passive scanning mode, the Wi-Fi access points (e.g., 110a/1700a, 110b/1700b, 110c/1700c, and 110d/1700d) physically and logically associated with assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) may broadcast beacon frames (not shown) at regular intervals, each of which includes information that uniquely identifies the particular Wi-Fi access point <NUM>/<NUM> and, to those who recognize the association, by proxy the asset (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) associated with it. One or more wireless devices <NUM> may come in-range of one or more Wi-Fi access points <NUM>/<NUM> and receive one or more beacon frames. As previously discussed, wireless devices <NUM> report, via a cellular or other connection, information such as, for example, the time, the date, its current location, its speed, or direction of travel, as well as the SSID and BSSID of in-range Wi-Fi access points <NUM>/<NUM> encountered to a computing system <NUM> of an original equipment manufacturer of the wireless device <NUM>, an operating system developer (not shown), third-party software developer (not shown), or a dedicated asset tracking system of the present invention (not shown) that tracks assets. While the encounter reporting feature of wireless devices <NUM> is typically used to improve the accuracy of location-based services, here, the reporting feature provides, clandestinely, an estimate of the location of one or more Wi-Fi access points <NUM>/<NUM> at a particular time and date without requiring the purposeful participation of any particular wireless device <NUM> in any particular Wi-Fi wireless network. This information may be used to determine the location of one or more Wi-Fi access points <NUM>/<NUM> and, by proxy, one or more assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) with substantial accuracy, that may be further refined with well-known Wi-Fi access point triangulation processes typically used by wireless devices <NUM> to refine GPS accuracy or improve location services.

In other embodiments, in active scanning mode, one or more wireless devices <NUM> may transmit a probe request frame (not shown) that is not directed to any particular Wi-Fi access point, requesting that all Wi-Fi access points <NUM>, including dummy Wi-Fi access points <NUM>, in range announce their presence. In response, in-range Wi-Fi access points <NUM>/<NUM> may transmit a probe response frame which includes information that uniquely identifies the responding Wi-Fi access point <NUM>/<NUM> and, to those who recognize the association, the asset (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) associated with it. As previously discussed, wireless devices <NUM> report, via a cellular or other connection, information such as, for example, the time, the date, its current location, its speed, or direction of travel, as well as the SSID and BSSID of in-range Wi-Fi access points <NUM>/<NUM> encountered to a computing system <NUM> of an original equipment manufacturer (not shown) of the wireless device <NUM>, an operating system developer (not shown), third-party software developer (not shown), or a dedicated asset tracking system of the present invention (not shown) that tracks assets.

While a single wireless device <NUM> is depicted in the figure, one of ordinary skill in the art will recognize that any number of wireless devices <NUM> may come in and out of range of the assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) over time, each of which independently reports the time, the date, their location, and the SSID and BSSID of in-range Wi-Fi access points <NUM>/<NUM> as they are encountered (and other information that may be useful to the asset tracking task). In fact, the tracking accuracy may improve as a function of the number of unique identifications that take place over time, or potentially provide additional information such as movement of assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) throughout the day, or the speeds at which they are moving, or even when they leave a boundary of the job site <NUM>. While wireless device <NUM> is depicted as being disposed in a motor vehicle <NUM> driving <NUM> by a job site <NUM>, one of ordinary skill in the art will recognize that wireless device <NUM> may be stationary or conveyed by any means conceived of so long as it is capable of participating in Wi-Fi wireless network discovery and thereby identifying, reporting, and effectively locating assets (e.g., <NUM>, <NUM>, <NUM>, and <NUM>) indirectly by reporting the Wi-Fi access points <NUM>/<NUM> encountered.

<FIG> shows a system <NUM> for passive asset tracking with existing infrastructure in accordance with one or more embodiments of the present invention. One or more Wi-Fi access points <NUM>/<NUM> may be disposed, or otherwise attached to, or integrated with, one or more assets (e.g., <NUM>) that are desired to be tracked. The unique identifying information of a Wi-Fi access point <NUM>/<NUM> may be used to uniquely identify an asset (e.g., <NUM>) that it is physically and logically associated with in an asset tracking database <NUM>. The one or more assets (e.g., <NUM>) may be deployed in the field and need not be co-located. The deployed Wi-Fi access points <NUM>/<NUM> do not require Internet connectivity or other network connection or be configured to receive GPS signals, they simply must be powered on and either broadcast beacon frames or respond to probe request frames, with a probe response frame, as part of the Wi-Fi wireless network discovery process.

When one or more wireless devices (e.g., <NUM>) come into range of one or more of the Wi-Fi access points <NUM>/<NUM> disposed, or otherwise attached to, or integrated with, one or more assets (e.g., <NUM>), the in-range Wi-Fi access points <NUM>/<NUM> may either broadcast their beacon frame or respond to a probe request frame with a probe response frame including information that may be used to uniquely identify the corresponding assets (e.g., <NUM>) and potentially other information that may be useful to the asset tracking task including custom use of certain information in the beacon frame or probe response frame. As noted above, the one or more wireless devices <NUM> typically report the time, the date, their current location, as well as the SSID and the BSSID of the in-range Wi-Fi access points <NUM>/<NUM> encountered and discovered either directly to an asset tracking database <NUM> or to a Wi-Fi AP Database <NUM> (third-party or integrated) that may provide data to asset tracking database <NUM>. Wi-Fi AP Database <NUM> may be a database managed by an original equipment manufacturer, an operating system developer, or a third-party software developer, or a database integrated with asset tracking database <NUM>. In certain embodiments, Wi-Fi AP Database <NUM> may be part of iOS® or Android® location services used to improve location determination accuracy. Asset tracking database <NUM> may use the data provided directly by one or more wireless devices <NUM> or indirectly by way of, for example, Wi-Fi AP Database <NUM> to identify and locate one or more assets (e.g., <NUM>), the data of which may be stored in asset tracking database <NUM>. Depending on the type of data received, asset tracking database <NUM> may manipulate, extrapolate, or otherwise generate data stored therein. A client portal <NUM>, which may be software executed on another computing system (not shown), executed on the same computer (not shown) as the asset tracking database <NUM>, or an application (not shown) or web-based portal thereof executed on a wireless device (e.g., <NUM>), may allow a user to interact with asset tracking database <NUM> and obtain relevant data contained therein.

In certain embodiments, system <NUM> for passive asset tracking with existing infrastructure may include asset tracking database <NUM> and may optionally include client portal <NUM>. In other embodiments, system <NUM> may optionally include Wi-Fi AP Database <NUM>, which is typically independent of system <NUM>, as part of a closed wholistic embodiment of system <NUM>. In such embodiments, Wi-Fi AP Database <NUM> may reside or execute on the same or a different computing system as that of asset tracking database <NUM> or be integrated with asset tracking database <NUM> or a software application thereof. In still other embodiments, system <NUM> may optionally include one or more Wi-Fi access points <NUM>/<NUM> disposed on, otherwise attached to, or integrated with, one or more assets (e.g., <NUM>). In still other embodiments, system <NUM> may optionally include one or more wireless devices <NUM>, which are typically independent of system <NUM>, that purposefully discover in-range Wi-Fi access points <NUM>/<NUM>, as part of a closed wholistic embodiment of system <NUM>. In such embodiments, wireless device <NUM> may include dedicated software (not shown) that reports the time, the date, and the SSID and the BSSID of Wi-Fi access points <NUM>/<NUM> it encounters to asset tracking database <NUM> or Wi-Fi AP Database <NUM>, if integrated. While various embodiments of system <NUM> have been disclosed, one of ordinary skill in the art will recognize that a subset, superset, or combination of functions or features thereof, may be integrated, distributed, or excluded, in whole or in part, based on an application, design, or form factor in accordance with one or more embodiments of the present invention and the above-disclosure is not intended to limit the type, kind, or arrangement of system <NUM> that may be implemented, including those that include, integrate, separate, or exclude various aspects or features thereof.

Continuing, <FIG> shows exemplary data <NUM> reported by a wireless device <NUM> relating to encountered Wi-Fi access points <NUM>/<NUM> in accordance with one or more embodiments of the present invention. Wireless device <NUM> may report, for example, identifying information of one or more in-range Wi-Fi access points <NUM>/<NUM>, their relative signal strength, as well as the time, the date, and the GPS location of the reporting wireless device <NUM>, to asset tracking database <NUM> or Wi-Fi AP Database <NUM>. The identifying information may include one or more of the SSID, the BSSID, or other information that may be used to uniquely identify the Wi-Fi access point <NUM>/<NUM> including potentially other fields of the beacon frames, probe response frames, or other management frames that may be repurposed to convey information regarding the Wi-Fi access point <NUM>/<NUM> or the asset it is associated with. For example, the BSSID of a Wi-Fi access point <NUM> may be a unique identifier of the asset it is physically (by way of location, attachment, or integration) and logically (by way of asset tracking database <NUM>) associated with. In addition, the MAC address, SSID, or other field may be used to identify a Wi-Fi access point <NUM>/<NUM> as an asset tracking type of Wi-Fi access point. In the future, such functionality could allow wireless devices <NUM> to take different action when an asset tracking type Wi-Fi access point is encountered, including potentially speeding up the identification, changes the nature of the reporting, or otherwise facilitating the asset tracking task. One of ordinary skill in the art will recognize that the type and kind of information reported by the wireless device <NUM> relating to a discovered Wi-Fi access point <NUM>/<NUM> or an asset (e.g., <NUM>) associated therewith may vary based on an application or design in accordance with one or more embodiments of the present invention, but must at least include information that uniquely identifies the Wi-Fi access point <NUM>/<NUM>.

Continuing, <FIG> shows exemplary data <NUM> stored or generated by asset tracking database <NUM> in accordance with one or more embodiments of the present invention. Asset tracking database <NUM> may associate unique identifying information, such as, for example, the BSSID, of a particular Wi-Fi access point <NUM>/<NUM> with a particular asset (e.g., <NUM>) on which it is disposed, attached to, or integrated with. As such, asset tracking database <NUM> may then use information relating to the discovery of one or more Wi-Fi access points <NUM>/<NUM> that is reported by one or more wireless devices <NUM> to passively track one or more assets (e.g., <NUM>) in an indirect manner, in many instances without an awareness by wireless devices <NUM>, or users thereof, that they are participating in the asset tracking task.

Asset tracking database <NUM> may receive and store identifying information relating to a particular Wi-Fi access point <NUM>/<NUM> that is logically associated within the database <NUM> with a particular asset (e.g., <NUM>) and may include the time, date, and GPS location of the wireless device <NUM> that reported the particular Wi-Fi access point <NUM>/<NUM>. Asset tracking database <NUM> may also receive and store other information relating to the particular asset (e.g., <NUM>) provided, directly or indirectly, by one or more wireless devices <NUM>. Asset tracking database <NUM> may either receive, or determine through historical information or calculation, the last known location of the particular Wi-Fi access point <NUM>/<NUM>, and by relation, the particular asset (e.g., <NUM>). Asset tracking database <NUM> may also receive identifying information, the signal strength, the time, date, and GPS location of one or more wireless devices <NUM> reporting other discovered Wi-Fi access points <NUM>/<NUM>. As such, asset tracking database <NUM> may use any information, including, potentially, times, dates, GPS locations, last known positions, and signal strengths to known Wi-Fi access points <NUM>/<NUM> and well known trilateration or triangulation techniques to refine the accuracy of the location determination of the particular Wi-Fi access point <NUM>/<NUM> and, by relation, the particular asset (e.g., <NUM>). As such, asset tracking database <NUM> may develop a historical trend of location and potentially other information relating to the particular asset (e.g., <NUM>) over a period of time.

Asset tracking database <NUM> may have a data structure that may include, but is not limited to, one or more of the time, date, GPS location, latitude ("GPS LAT"), longitude ("GPS LNG"), SSID, BSSID, and signal strength of an encountered Wi-Fi access point <NUM>/<NUM> as part of each report, received directly or indirectly, from a wireless device <NUM> that encounters an in-range Wi-Fi access point <NUM>/<NUM>. The BSSID of the discovered Wi-Fi access point <NUM>/<NUM> may be associated with, or used to reference, a particular asset (e.g., <NUM>) being tracked.

Asset tracking database <NUM> may receive, calculate, or estimate a last known ("AP LK") position of the discovered Wi-Fi access point <NUM>/<NUM>. If a last know position of a Wi-Fi access point <NUM>/<NUM> is not known, it may be estimated by the GPS location of the most recent wireless device <NUM> that reported discovery of the Wi-Fi access point <NUM>/<NUM> or further refined with Wi-Fi triangulation or trilateration techniques. Asset tracking database <NUM> may, based on available information, calculate a current ("AP CUR") location for one or more Wi-Fi access points <NUM>/<NUM>, and by relation, the associated assets (e.g., <NUM>) thereof. One of ordinary skill in the art will appreciate that calculating a location based on the last known location of one or more Wi-Fi access points, if any, the GPS locations of one or more wireless devices <NUM> reporting the Wi-Fi access points <NUM>/<NUM>, if available, and their relative signal strengths, and potentially other information relating thereto, may be used to determine or refine the location determination of one or more Wi-Fi access points <NUM>/<NUM>, and assets associated therewith, using well known Wi-Fi location refinement techniques. The calculated current location may be stored in asset tracking database <NUM> as the best estimate where a particular Wi-Fi access point <NUM>/<NUM>, and by relation, asset (e.g., <NUM>) may be located.

One of ordinary skill in the art will recognize that asset tracking database <NUM> may receive, generate, or store other data relating to a Wi-Fi access point <NUM>/<NUM>, an asset (e.g., <NUM>) associated therewith, or other metrics based on an application or design in accordance with one or more embodiments of the present invention.

<FIG> shows an exemplary client portal <NUM> to asset tracking database <NUM> in accordance with one or more embodiments of the present invention. A user (not shown) may access the data contained within asset tracking database <NUM> via client portal <NUM> accessible via the same computer (not shown) on which the asset tracking database <NUM> is resident and executing, on another computer (not shown) with a network connection to asset tracking database <NUM>, or via a software application potentially resident and executing on a wireless device (not shown), or web-based portal thereof, with a network connection to asset tracking database <NUM>. One of ordinary skill in the art will recognize that client portal <NUM> may be disposed on any computer based on an application or design in accordance with one or more embodiments of the present invention. Client portal <NUM> may provide the user with the ability to access at least some of the data stored in asset tracking database <NUM>. For example, a user may inquire as to the location of a specific asset. Client portal <NUM> may lodge the query with asset tracking database <NUM>, receive the requested data, which in this case, may be the unique identifying information of the asset as well as its last known location. One of ordinary skill in the art will recognize that the interface, interaction with, and display of, data by client portal <NUM> may vary based on an application or design and may include graphical output (not shown), such as, for example, locations on a map where assets are located, in accordance with one or more embodiments of the present invention.

In one or more embodiments of the present invention, a method of passive asset tracking with existing independent infrastructure may include disposing a Wi-Fi access point on, in, or otherwise attaching to, or integrating with, a moveable physical asset to be tracked. The Wi-Fi access point may be a conventional off-the-shelf, industrial, battery-powered, or any other type or kind of Wi-Fi access point. However, because the Wi-Fi access point does not require routing features or true Wi-Fi functionality beyond that of participating in the Wi-Fi wireless network discovery protocol, custom Wi-Fi access points, such as, for example, dummy Wi-Fi access point <NUM>, that may eliminate features not implemented may be used to reduce the footprint and the power consumption of such a device. In addition, devices that spoof the Wi-Fi wireless network discovery protocol, such as, for example, dummy Wi-Fi access point <NUM>, may be used specifically for the asset tracking task. Notwithstanding, one of ordinary skill in the art will recognize that any Wi-Fi access point, or related device, capable of participating in Wi-Fi wireless network discovery protocol may be used in accordance with one or more embodiments of the present invention.

The method may further include logically associating unique identifying information of the Wi-Fi access point with the asset in an asset tracking database. The unique identifying information may be any information that uniquely identifies the Wi-Fi access point including, for example, the BSSID of the Wi-Fi access point. The asset tracking database may be any type or kind of database or software application that stores and potentially manipulates data. The Wi-Fi access point associated with a particular moveable asset may be stored in the same or a related record in the asset tracking database or otherwise related indicating their association, specifically, using the location of the Wi-Fi access point as a proxy for the location of the asset.

The method may further include receiving information relating to a location of the Wi-Fi access point encountered by one or more wireless devices and storing at least part of the information received in the asset tracking database. In certain embodiments, the information relating to the location of the Wi-Fi access point encountered is received directly or indirectly from a Wi-Fi AP Database or third-party provider. In other embodiments, the information relating to the location of the Wi-Fi access point encountered is received directly or indirectly from one or more of the reporting wireless devices. In certain embodiments, the one or more wireless devices, or users thereof, may not be aware that they are participating in the asset tracking task. The wireless devices simply report their location and the unique identifying information of Wi-Fi access points they encounter, typically as part of their participation in location services. In other embodiments, the one or more wireless devices may be used to intentionally participate in the asset tracking task. In all such embodiments, whenever a wireless device comes in-range of a Wi-Fi access point and receives unique identifying information about the Wi-Fi access point, the wireless device reports at least its location and the unique identifying information of the Wi-Fi access point, typically over a cellular connection, directly or indirectly to one or more of an original equipment manufacturer, an operating system developer, a location-based services provider, a Wi-Fi AP Database, or a third-party software application or database, or directly to the asset tracking database itself. The information relating to the location of the wireless device may include, for example, a time, date, GPS location of the reporting wireless device, last known location of the Wi-Fi access point, the unique identifying information of other in-range Wi-Fi access points, and their respective signal strengths. One of ordinary skill in the art will recognize that other information may be used and may vary based on an application or design in accordance with one or more embodiments of the present invention. As such, the information relating to the location of the Wi-Fi access point may be received by the asset tracking database directly or indirectly from one or more wireless devices that report their location as well as the unique identifying information of one or more Wi-Fi access points that they encounter.

The method may further include tracking the location of the Wi-Fi access point, and by relation, the asset itself, in the asset tracking database. The asset tracking database may maintain a record of reports relating to the Wi-Fi access point and receive or calculate an estimated location for the Wi-Fi access point, and by relation, the asset itself. This information may be stored in the asset tracking database as the estimated current location of the asset with any other information suitable for storing in the asset tracking database. As noted above, the asset tracking database may receive information that provides an estimate of a location of the Wi-Fi access point or information that may be used to estimate the location of the Wi-Fi access point using one or more of GPS determined locations, Wi-Fi access point locations and potentially associated signal strengths, trilateration, or triangulation. The method may further include providing a user access to information stored in the asset tracking database via a client portal. The client portal may include a software interface for querying and receiving information from the asset tracking database. The client portal may be part of the same computing system as that of the asset tracking database or a separate and distinct computing system or wireless device that connects to the asset tracking database over a network connection. In one or more embodiments of the present invention, a non-transitory computer readable medium comprising software instructions, when executed by a processor, may perform any of the above-noted methods.

In one or more embodiments of the present invention, a system for passive asset tracking with existing independent infrastructure may include a computing system having a central processing unit, a system memory, a network interface, and a storage device and a Wi-Fi access point disposed on, in, or otherwise attached to, a moveable asset to be tracked. An asset tracking database executing on the computing system may associate unique identifying information of the Wi-Fi access point with the asset. The asset tracking database may receive information relating to a location of the Wi-Fi access point identified by its unique identifying information transmitted as part of Wi-Fi wireless network discovery. The asset tracking database may track the location of the Wi-Fi access point and, by relation, the associated asset.

<FIG> shows a computing system <NUM> in accordance with one or more embodiments of the present invention. One or more of asset tracking database (e.g., <NUM> of <FIG>), Wi-Fi AP Database (e.g., <NUM> of <FIG>), or client portal (e.g., <NUM> of <FIG>) may be software applications containing software instructions that, when executed by a processor of a computing system <NUM>, perform one or more of the above-noted methods. One of ordinary skill in the art will recognize that a computing system <NUM> disclosed herein is merely exemplary of a computing system that may be used to execute any of the above-noted software and other computing systems well known in the art may be used in accordance with one or more embodiments of the present invention.

Computing system <NUM> may include one or more central processing units, sometimes referred to as processors (hereinafter referred to in the singular as "CPU" or plural as "CPUs") <NUM>, host bridge <NUM>, input/output ("IO") bridge <NUM>, graphics processing units (singular "GPU" or plural "GPUs") <NUM>, and/or application-specific integrated circuits (singular "ASIC or plural "ASICs") (not shown) disposed on one or more printed circuit boards (not shown) that perform computational operations. Each of the one or more CPUs <NUM>, GPUs <NUM>, or ASICs (not shown) may be a single-core (not independently illustrated) device or a multi-core (not independently illustrated) device. Multi-core devices typically include a plurality of cores (not shown) disposed on the same physical die (not shown) or a plurality of cores (not shown) disposed on multiple die (not shown) that are collectively disposed within the same mechanical package (not shown).

CPU <NUM> may be a general-purpose computational device that executes software instructions. CPU <NUM> may include an interface <NUM> to host bridge <NUM>, an interface <NUM> to system memory <NUM>, and an interface <NUM> to one or more IO devices, such as, for example, one or more GPUs <NUM>. GPU <NUM> may serve as a specialized computational device that performs graphics functions related to frame buffer manipulation. However, one of ordinary skill in the art will recognize that GPU <NUM> may be used to perform non-graphics related functions that are computationally intensive. In certain embodiments, GPU <NUM> may interface <NUM> directly with CPU <NUM> (and interface <NUM> with system memory <NUM> through CPU <NUM>). In other embodiments, GPU <NUM> may interface <NUM> with host bridge <NUM> (and interface <NUM> or <NUM> with system memory <NUM> through host bridge <NUM> or CPU <NUM> depending on the application or design). In still other embodiments, GPU <NUM> may interface <NUM> with IO bridge <NUM> (and interface <NUM> or <NUM> with system memory <NUM> through host bridge <NUM> or CPU <NUM> depending on the application or design). The functionality of GPU <NUM> may be integrated, in whole or in part, with CPU <NUM>.

Host bridge <NUM> may be an interface device that interfaces between the one or more computational devices and IO bridge <NUM> and, in some embodiments, system memory <NUM>. Host bridge <NUM> may include an interface <NUM> to CPU <NUM>, an interface <NUM> to IO bridge <NUM>, for embodiments where CPU <NUM> does not include an interface <NUM> to system memory <NUM>, an interface <NUM> to system memory <NUM>, and for embodiments where CPU <NUM> does not include an integrated GPU <NUM> or an interface <NUM> to GPU <NUM>, an interface <NUM> to GPU <NUM>. The functionality of host bridge <NUM> may be integrated, in whole or in part, with CPU <NUM>. IO bridge <NUM> may be an interface device that interfaces between the one or more computational devices and various IO devices (e.g., <NUM>, <NUM>) and IO expansion, or add-on, devices (not independently illustrated). IO bridge <NUM> may include an interface <NUM> to host bridge <NUM>, one or more interfaces <NUM> to one or more IO expansion devices <NUM>, an interface <NUM> to keyboard <NUM>, an interface <NUM> to mouse <NUM>, an interface <NUM> to one or more local storage devices <NUM>, and an interface <NUM> to one or more network interface devices <NUM>. The functionality of IO bridge <NUM> may be integrated, in whole or in part, with CPU <NUM> and/or host bridge <NUM>. Each local storage device <NUM>, if any, may be a solid-state memory device, a solid-state memory device array, a hard disk drive, a hard disk drive array, or any other non-transitory computer readable medium. Network interface device <NUM> may provide one or more network interfaces including any network protocol suitable to facilitate networked communications.

Computing system <NUM> may include one or more network-attached storage devices <NUM> in addition to, or instead of, one or more local storage devices <NUM>. Each network-attached storage device <NUM>, if any, may be a solid-state memory device, a solid-state memory device array, a hard disk drive, a hard disk drive array, or any other non-transitory computer readable medium. Network-attached storage device <NUM> may or may not be collocated with computing system <NUM> and may be accessible to computing system <NUM> via one or more network interfaces provided by one or more network interface devices <NUM>.

One of ordinary skill in the art will recognize that computing system <NUM> may be a conventional computing system or an application-specific computing system (not shown). In certain embodiments, an application-specific computing system (not shown) may include one or more ASICs (not shown) that perform one or more specialized functions in a more efficient manner. The one or more ASICs (not shown) may interface directly with CPU <NUM>, host bridge <NUM>, or GPU <NUM> or interface through IO bridge <NUM>. Alternatively, in other embodiments, an application-specific computing system (not shown) may be reduced to only those components necessary to perform a desired function in an effort to reduce one or more of chip count, printed circuit board footprint, thermal design power, and power consumption. The one or more ASICs (not shown) may be used instead of one or more of CPti <NUM>, host bridge <NUM>, IO bridge <NUM>, or GPU <NUM>. In such systems, the one or more ASICs may incorporate sufficient functionality to perform certain network and computational functions in a minimal footprint with substantially fewer component devices.

As such, one of ordinary skill in the art will recognize that CPU <NUM>, host bridge <NUM>, IO bridge <NUM>, GPU <NUM>, or ASIC (not shown) or a subset, superset, or combination of functions or features thereof, may be integrated, distributed, or excluded, in whole or in part, based on an application, design, or form factor in accordance with one or more embodiments of the present invention. Thus, the description of computing system <NUM> is merely exemplary and not intended to limit the type, kind, or configuration of component devices that constitute a computing system <NUM> suitable for executing software methods in accordance with one or more embodiments of the present invention. Notwithstanding the above, one of ordinary skill in the art will recognize that computing system <NUM> may be a standalone, laptop, desktop, industrial, server, blade, or rack mountable system and may vary based on an application or design.

A sensor is a well-known type of device that senses an aspect of the physical environment in which it is located. Sensors typically detect or measure a physical property and record, transmit, or act in response to the sensed physical property. Internet-connected sensors typically connect to a Wi-Fi client that identifies, authenticates to, and associates with, an in-range Wi-Fi access point that provides upstream network connectivity. In this way, the Internet-connected sensor may transmit sensor data to the Wi-Fi access point that is routed from the Wi-Fi access point to the bridged network connection, typically the Internet, for transmission to its final destination. In other applications, the sensor connects to a cellular modem that routes the sensor data to an upstream network connection. And in still other applications, the sensor connects directly to an upstream network connection.

In contrast to Internet-connected sensors, RFID tags store data and provide localized communications with an RFID reader that is in close proximity with the RFID tag. While the RFID reader may transmit RFID tag data upstream, the communication between the RFID reader and the RFID tag itself is localized. The RFID tag remains dormant until it receives an electromagnetic interrogation pulse from a nearby RFID reader. The electromagnetic interrogation pulse triggers the RFID tag to transmit the data stored in the RFID tag to the RFID reader. The RFID reader may transmit the data to its final destination via an upstream network connection. While some RFID applications incorporate a sensor, similar to Internet-connected sensors, RFID sensor tags require close proximity to an RFID reader in order to transmit the sensor data and the RFID reader must provide an upstream network connection in order to transmit the data to its final destination.

While Internet-connected sensors and RFID sensor tags have found widespread application, the trend towards ubiquitous Wi-Fi connectivity has given rise to a new paradigm, referred to as the Internet of Things ("IoT"). In a general sense, IoT involves the application of Internet connectivity to atypical devices that derive some benefit from the connectivity. In the sensor context, IoT sensors may be thought of as any type of sensor that is capable of sending or receiving sensor data via a network connection, such as the Internet. As such, IoT sensors integrate a Wi-Fi client, typically in the microcontroller, that is used to identify, authenticate to, and associate with an in-range Wi-Fi access point that routes the sensor data to its final destination via an upstream network connection. Because of the size and power constraints imposed on most IoT applications, communications are difficult unless the IoT sensor is placed in close proximity to the Wi-Fi access point or the signal strength is sufficiently strong to enable communications. However, IoT sensors, like Internet-connected sensors, RFID sensor tags, and all other Wi-Fi clients, must identify, authenticate to, and associate with, a Wi-Fi access point in order to transmit data to an upstream network connection for routing to its final destination. As such, the power constraints, complex setup, and ongoing administration frustrate the intent of IoT. Moreover, IoT sensors may only be deployed in locations within range of a suitable Wi-Fi access point that provides the upstream network connection. A common shortcoming of Internet-connected sensors, RFID tag sensors, and IoT sensors is that, they require a Wi-Fi client that identifies, authenticates to, and associates with, a Wi-Fi access point, that provides an upstream network connection, in order to transmit their sensor data.

Accordingly, in one or more embodiments of the present invention, a method of, and system for, passive sensor tracking with existing infrastructure uses a passive sensor that spoofs a beacon, probe response, or other management frame and places sensor data in a field that is reported by a Wi-Fi client, typically as part of location services, as part of reporting an encounter with a Wi-Fi access point. When a Wi-Fi client, such as a smartphone, encounters the Wi-Fi access point of the passive sensor, the beacon, probe response, or other management frame transmitted by the passive sensor includes sensor data in a field that is reported by the Wi-Fi client to a Wi-Fi AP Database or sensor tracking database that logs encountered Wi-Fi access points, typically as part of location services. Advantageously, a passive sensor may be deployed to sense a physical property in a location where no Wi-Fi access points or upstream network connectivity exists, relying instead on random Wi-Fi clients that happen to encounter the Wi-Fi access point of the passive sensor and merely report their encounter with the Wi-Fi access point to a third-party Wi-Fi AP Database or sensor tracking database, typically as part of location services. The report of the encounter may include, without awareness on the part of the user or Wi-Fi client, information relating to the Wi-Fi access point encountered, including, but not limited to, the BSSID and SSID. However, the Wi-Fi access point of the passive sensor transmits a beacon, probe response, or other management frame that places sensor data in a reported field such as, for example, the BSSID or SSID. In this way, a passive sensor may be deployed in an area with no network connectivity, relying instead on the existing infrastructure provided by the community of smartphones. Even if the smartphone has no cellular connection at the time of the encounter with the Wi-Fi access point, it may log the encounter and report it at a later time when it re-establishes connectivity. A sensor tracking database may obtain the sensor data directly or indirectly from the Wi-Fi AP Database and in some embodiments, from the wireless clients themselves, and make it available to a user that wishes to monitor the passive sensor. Accordingly, sensor data may be transmitted without authenticating to, or associating with, a Wi-Fi access point, and without requiring that the Wi-Fi access point provide access to an upstream network connection. In this way, passive sensors may be tracked using the existing infrastructure provided by the community of wireless devices that merely happen to encounter the passive sensors, without requiring an awareness on the part of the wireless device, or user thereof, that they are participating in the sensor tracking task.

<FIG> shows a sequence of management frames <NUM> exchanged between a conventional Wi-Fi client <NUM> and a conventional Wi-Fi access point <NUM> as part of Wi-Fi wireless network discovery. A conventional Internet-connected sensor (not shown), RFID reader of an RFID sensor tag (not shown), or IoT sensor (not shown) must integrate, or at least connect to, Wi-Fi client <NUM>, and must successfully identify, authenticate to, and associate with, Wi-Fi access point <NUM> in order to transmit sensor data as part of data frames <NUM>. As previously discussed, Wi-Fi wireless network discovery refers to the process by which a wireless device, such as a Wi-Fi client <NUM>, identifies, authenticates to, and associates with, an in-range Wi-Fi access point <NUM> to enable data transfer with an upstream network connection <NUM>.

The IEEE <NUM> standard specifies a protocol that includes three different types of frames: management frames, data frames, and control frames. Each type of frame serves a specific purpose with respect to the protocol. For example, management frames are used for supervisory functions including Wi-Fi wireless network discovery, data frames are used to transmit data once authenticated and associated, and control frames are used to facilitate the transmission of data. The IEEE <NUM> standard also specifies two different scenarios by which Wi-Fi clients <NUM> may identify, authenticate to, and associate with, Wi-Fi access points <NUM> as part of Wi-Fi wireless network discovery.

In passive scanning mode, a Wi-Fi client <NUM> listens for beacon frames <NUM>, a type of management frame, that is broadcast at periodic intervals by a Wi-Fi access point <NUM>. The beacon frame <NUM> announces the presence of the Wi-Fi access point <NUM> and includes information that facilitates potential authentication to, association with it, and ultimately data transmission, including, for example, the BSSID and SSID of the broadcasting Wi-Fi access point <NUM>. For example, the user of a wireless device <NUM>, such as, for example, a smartphone, may open the Wi-Fi application on their device, see a list of SSIDs corresponding to in-range Wi-Fi access points <NUM> that are broadcasting their respective beacon frames (e.g., <NUM>), and select a particular SSID of a particular Wi-Fi access point <NUM> that the user wishes to join. When the user selects the SSID of a particular Wi-Fi access point <NUM>, the Wi-Fi client <NUM> transmits a probe request frame <NUM>, another type of management frame, to the particular Wi-Fi access point <NUM> that includes the capabilities of the Wi-Fi client <NUM>. In the active scanning mode, without necessarily having received a beacon frame <NUM>, the Wi-Fi client <NUM> transmits a probe request frame <NUM> that includes the capabilities of the Wi-Fi client <NUM> to a specific Wi-Fi access point <NUM> or all Wi-Fi access points <NUM> in range. As such, the Wi-Fi wireless network discovery process may be initiated by a Wi-Fi access point <NUM> that broadcasts beacon frames <NUM>, or a Wi-Fi client <NUM> that transmits a probe request frame <NUM>. Regardless of which, the remainder of the authentication and association protocol is substantially the same.

Subsequent to receipt of the probe request frame <NUM>, if the Wi-Fi access point <NUM> has compatible parameters, the Wi-Fi access point <NUM> transmits a probe response frame <NUM>, another type of management frame, to the Wi-Fi client <NUM>. The probe response frame <NUM> includes the parameters typically included in the beacon frame <NUM> including capabilities of the Wi-Fi access point <NUM>. It is important to note that, at this stage of the process, the Wi-Fi client <NUM> is unauthenticated to, and unassociated with, the Wi-Fi access point <NUM>, and is not capable of transmitting data in data frames. Subsequent to receipt of the probe response frame <NUM>, the Wi-Fi client <NUM> transmits an authentication request frame <NUM>, another type of management frame, to the Wi-Fi access point <NUM>. The authentication protocol establishes whether the Wi-Fi client <NUM> is authenticated to the Wi-Fi access point <NUM>, i.e., ensuring compatibility with respect to encryption (open or shared key encryption). Without discussing the details of the authentication protocol, which is unnecessary for the purpose of describing the claimed invention, it is important to note that a Wi-Fi client <NUM> cannot proceed to association and data transfer until it is has been successfully authenticated to the Wi-Fi access point <NUM>, as signified by an authentication response frame <NUM>, another type of management frame, acknowledging successful authentication.

Once authenticated to Wi-Fi access point <NUM>, Wi-Fi client <NUM> transmits an association request frame <NUM>, another type of management frame, to Wi-Fi access point <NUM>. The association request frame <NUM> signifies a request by the authenticated, but as yet unassociated Wi-Fi client <NUM> to associate with the Wi-Fi access point <NUM> and enable data transfer via data frames <NUM>. The association request <NUM> includes information including, for example, capabilities of the Wi-Fi client <NUM>. After receipt of the association request <NUM>, the Wi-Fi access point <NUM> compares the capabilities set out in the association request <NUM> with the capabilities of the Wi-Fi access point <NUM> to determine if they match. If there is a mismatch, the Wi-Fi access point <NUM> makes a determination as to whether the difference is an issue that prevents association and data transfer. If there are no differences, or the differences do not prevent association, the Wi-Fi access point <NUM> transmits an association response <NUM>, another type of management frame, acknowledging successful association. Once the association response <NUM> signifying successful association with Wi-Fi access point <NUM> is received, Wi-Fi client <NUM> may transmit data <NUM> to Wi-Fi access point <NUM> in data frames that are routed over a bridged network connection, typically the Internet <NUM>, to its final destination. It is important to note that, in order for a Wi-Fi client <NUM> to transmit data, other than management frames, with Wi-Fi access point <NUM>, the Wi-Fi client <NUM> must authenticate to, and associate with, Wi-Fi access point <NUM>, thereby enabling Wi-Fi client <NUM> to transmit data <NUM>. And similarly, Wi-Fi access point <NUM> cannot transfer data in data frames to Wi-Fi client <NUM> until Wi-Fi client <NUM> has authenticated to, and associated with, Wi-Fi access point <NUM>.

<FIG> shows the subtypes of management frames <NUM> defined by the IEEE <NUM> standard. In a conventional management frame (e.g., <NUM> of <FIG>), the first octet is defined as the Frame Control field (e.g., <NUM> of <FIG>). The first three subfields of the Frame Control field (e.g., <NUM> of <FIG>) are present in all IEEE <NUM> frames and include the protocol version (not shown), the type of frame, and the subtype of frame. The type of frame subfield indicates whether the frame is a management frame, data frame, or control frame. The subtype of frame subfield indicates the particular subtype of frame within the type. In the figure, the various subtypes of management frames are shown. The subtype bits <NUM> represent the binary encoded subtype described by the subtype description <NUM>. For purposes of the discussion that follows, emphasis will be placed on the beacon frame and probe response frame subtypes of management frames. Notwithstanding, as can be seen by the enumerated list of management frames, other management frames used for supervisory purposes relating to identification, authentication, and association by conventional Wi-Fi clients (e.g., <NUM> of <FIG>) may be used in accordance with one or more embodiments of the present invention.

<FIG> shows the structure of a conventional management frame <NUM> defined by the IEEE <NUM> standard representative of the type of management frames transferred between a conventional Wi-Fi client (e.g., <NUM> of <FIG>) and a conventional Wi-Fi access point (e.g., <NUM> of <FIG>). The conventional management frame <NUM> includes a number of predetermined fields that are defined by the specification for their protocol-defined purpose. For example, MAC header <NUM> of management frame <NUM>, includes Frame Control field <NUM>, Duration field <NUM>, Destination Address field <NUM>, Source Address field <NUM>, BSSID <NUM>, and Sequence Control field <NUM>. Management frame <NUM> further includes the Frame Body field <NUM> that includes a number of subfields, including some that may vary based on the subtype (e.g., <NUM> of <FIG>) of management frame <NUM>. For example, Frame Body <NUM> includes mandatory subfields <NUM> including Timestamp subfield <NUM>, Beacon Interval subfield <NUM>, Compatibility Information subfield <NUM>, SSID subfield <NUM>, and potentially Supported Rates subfield (not shown). Frame Body field <NUM> may also include one or more optional subfields <NUM> that also may vary based on the subtype (e.g., <NUM> of <FIG>) of management frame <NUM>. The end of management frame <NUM> includes a Frame Check Sequence field <NUM> that includes an error-detecting code. During conventional Wi-Fi wireless network discovery, beacon frames, probe response frames, and other management frames are in the form of conventional management frame <NUM>, for the purpose of furthering identification, authentication to, and association with, a Wi-Fi access point (e.g., <NUM> of <FIG>).

<FIG> shows a block diagram of a passive sensor <NUM> in accordance with one or more embodiments of the present invention. In one or more embodiments of the present invention, passive sensor <NUM> may include a sensor portion <NUM>, a sensor interface <NUM>, a Wi-Fi access point <NUM>/<NUM>, and an antenna <NUM>. In certain embodiments, passive sensor <NUM> may include a conventional Wi-Fi access point <NUM> configured to spoof beacon frames, probe response frames, or other management frames that comprise sensor data. In other embodiments, passive sensor <NUM> may include a dummy Wi-Fi access point <NUM>. Sensor portion <NUM> may be any type or kind of device that senses a physical property and outputs a sensor signal comprising sensor data corresponding to the physical property sensed. For example, sensor portion <NUM> may sense a temperature and output an electrical signal corresponding to the temperature. While specific examples of various types and kinds of sensors are disclosed herein, one of ordinary skill in the art will recognize that the present invention is not limited and may be used with any type or kind of sensor portion <NUM>, which may vary based on an application or design in accordance with one or more embodiments of the present invention. Notwithstanding the above, sensor portion <NUM> may include, for example, without limitation, an acoustic sensor, ultrasonic sensor, infrared sensor, light sensor, color sensor, electric sensor, continuity sensor, resistance sensor, inductance sensor, capacitance sensor, electric field sensor, magnetic sensor, temperature sensor, thermal sensor, mechanical sensor, pressure sensor, humidity sensor, proximity sensor, contact sensor, tilt sensor, chemical sensor, moisture sensor, smoke sensor, gas sensor, alcohol sensor, seismic sensor, distance sensor, or touch sensor. Passive sensor <NUM> may also include a sensor interface <NUM> that inputs the sensor signal and generates sensor data corresponding to the physical property sensed, that may be placed or encoded in a field of a spoofed beacon frame, probe response frame, or other management frame that may be reported by a wireless device that encounters the Wi-Fi access point <NUM>/<NUM>, typically as part of location services or a direct or indirect report to a sensor tracking database.

In certain embodiments, passive sensor <NUM> may include an integrated Wi-Fi access point <NUM>. While fully capable chipsets may be used to implement Wi-Fi access point <NUM>, for the purposes of the claimed invention, Wi-Fi access point <NUM> may not allow any Wi-Fi client (e.g., <NUM> of <FIG>) to authenticate to, or associate with, Wi-Fi access point <NUM>. Further, Wi-Fi access point <NUM> may not provide upstream network connectivity. Instead, Wi-Fi access point <NUM> is only required to participate, potentially in a limited manner, in the Wi-Fi wireless network discovery process by transmitting spoofed beacon frames, probe response frames, or other management frames that comprise sensor data disposed or otherwise encoded therein. As such, in certain embodiments, Wi-Fi access point <NUM> may merely participate in a subset of the Wi-Fi wireless network- discovery process, to clandestinely transmit sensor data that is disposed or otherwise encoded, unbeknownst by the recipient Wi-Fi client (e.g., <NUM> of <FIG>), in the spoofed beacon frame, probe response frame, or other management frame.

In other embodiments, passive sensor <NUM> may include a dummy Wi-Fi access point <NUM>. For the purpose of this disclosure, a "dummy" Wi-Fi access point <NUM> is an device that imitates, or spoofs, a functional Wi-Fi access point by participating in the Wi-Fi wireless network discovery process by transmitting spoofed beacon frames, probe response frames, or other management frames that comprise sensor data disposed or otherwise encoded therein. However, a Wi-Fi client (e.g., <NUM> of <FIG>) may not be allowed to authenticate to, or associate with, dummy Wi-Fi access point <NUM> and dummy Wi-Fi access point <NUM> may not provide an upstream network connection. As such, in certain embodiments, dummy Wi-Fi access point <NUM> may merely participate, in a limited manner, in the Wi-Fi wireless network discovery process, to clandestinely transmit sensor data that is disposed or otherwise encoded, unbeknownst by the recipient Wi-Fi client (e.g., <NUM> of <FIG>), in the spoofed beacon frame, probe response frame, or other management frames.

When the Wi-Fi client (e.g., <NUM> of <FIG>) reports the encounter with the Wi-Fi access point <NUM> (or dummy Wi-Fi access point <NUM>), the Wi-Fi client (e.g., <NUM> of <FIG>) reports certain information about the encounter to a third-party Wi-Fi AP Database, typically for the purpose of enhancing location services, and in certain embodiments the report may be made directly or indirectly to a sensor tracking database. As previously discussed, Wi-Fi clients (e.g., <NUM> of <FIG>) report certain information about Wi-Fi access points that they encounter to a database, such as, for example, a Wi-Fi AP Database (not shown) that tracks this information, typically to enhance location services, or a dedicated sensor tracking database. Here, the sensor data may be clandestinely placed or encoded in the spoofed beacon frame, probe response frame, or other management frame, ensuring that the sensor data is stored in a field that is reported as part of the report of the encounter with the Wi-Fi access point <NUM>/<NUM>, typically for the purpose of enhancing location services.

Passive sensor <NUM> may also include an antenna <NUM> for purposes of transmitting spoofed beacon frame, probe response frame, or other management frames. While key aspects of a passive sensor <NUM> are shown, one of ordinary skill in the art will recognize that various aspects of a sensor that are well known are not descried to avoid obscuring the invention, including, for example, the type or kind of sensor, power input, and firmware. Moreover, one of ordinary skill in the art will recognize that the various portions of passive sensor <NUM>, or the functions or features they represent, may be integrated or distributed based on an application or design in accordance with one or more embodiments of the present invention.

<FIG> shows a spoofed management frame <NUM> transmitted by a Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>) in accordance with one or more embodiments of the present invention. Instead of using conventional management frames (e.g., <NUM> of <FIG>) for their intended use, in one or more embodiments of the present invention, sensor data may be placed or encoded, without awareness, in a spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame transmitted by the Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of the passive sensor <NUM>. In this way, a Wi-Fi client (e.g., <NUM> of <FIG>) that happens to encounter the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM>, will receive either the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (not shown) from the Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> that includes sensor data placed or encoded in the frame. Then, when the Wi-Fi client (e.g., <NUM> of <FIG>) reports the encounter with the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM>, the Wi-Fi client (e.g., <NUM> of <FIG>) reports, potentially without awareness, the sensor data to a Wi-Fi AP Database that typically tracks Wi-Fi access points to enhance location services or, directly or indirectly, to the sensor tracking database.

In one or more embodiments of the present invention, information including, but not limited to, unique identifying information of the passive sensor (e.g., <NUM> of <FIG>) and sensor data may be disposed or encoded in one or more fields of a spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame. While any field of the spoofed management frame <NUM> may be used, the one or more fields selected to place or encode sensor data may be selected such that they are fields that are reported by a Wi-Fi client (e.g., <NUM> of <FIG>) as part of a report of encounters with Wi-Fi access points, typically as part of the standard reporting feature used by location services. In the example depicted in the figure, BSSID field <NUM> may be used to uniquely identify the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of the passive sensor <NUM> and by association the passive sensor <NUM> itself. The sensor data, corresponding to a static or dynamic value, may be disposed or otherwise encoded in an appropriate field, either numeric or alphanumeric, with or without encoding. In the example depicted in the figure, SSID field <NUM> may be used to encode sensor data <NUM>. When a Wi-Fi client (e.g., <NUM> of <FIG>) encounters a Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>), the Wi-Fi client (e.g., <NUM> of <FIG>) reports, at least, BSSID <NUM> and SSID <NUM> of the Wi-Fi access point it encountered. Because the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>) or other management frame transmitted by the Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> includes sensor data <NUM>, the Wi-Fi client (e.g., <NUM> of <FIG>) will report the unique identifying information <NUM> of the passive sensor (e.g., <NUM> of <FIG>) and the sensor data <NUM>, potentially without awareness, to the Wi-Fi AP Database, which may be made available to a sensor tracking database (not shown) and clients thereof or directly or indirectly to the sensor tracking database itself.

<FIG> shows a sequence of management frames exchanged between a conventional Wi-Fi client <NUM> and a Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of a passive sensor <NUM> as part of Wi-Fi wireless network discovery in accordance with one or more embodiments of the present invention. As noted above, the Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> may only participate, in a limited manner, in Wi-Fi wireless network discovery. The Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) may transmit a spoofed beacon frame <NUM>, probe response frame <NUM>, or other management frame that comprises sensor data (e.g., <NUM> of <FIG>), but appear to be bona fide management frames (e.g., <NUM> of <FIG>) to the Wi-Fi client <NUM>. However, the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of passive sensor <NUM> is not required to allow the Wi-Fi client <NUM> to authenticate to, or associate with, the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) and the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) is not required to provide upstream network connectivity. In certain embodiments, the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) does not allow the Wi-Fi client <NUM> to authenticate to, or associate with, the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) and does not provides upstream network connectivity. The Wi-Fi client <NUM> cannot proceed to authentication or association and will not receive anything from the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) other than spoofed beacon frames <NUM>, probe response frames <NUM>, or other management frames (e.g., <NUM> of <FIG>) that comprises sensor data (e.g., <NUM> of <FIG>).

<FIG> shows an exemplary application <NUM> of an unaware, unauthenticated, and unassociated Wi-Fi client <NUM> receiving a spoofed management frame (e.g., <NUM> of <FIG>) from a Wi-Fi access point (e.g., <NUM> of <FIG>) or dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of a passive sensor <NUM> in accordance with one or more embodiments of the present invention. For the purposes of illustration, consider the example of a streetlight fixture <NUM> with passive sensor <NUM> that senses the state of the light bulb disposed therein. For example, passive sensor <NUM> may be a continuity sensor where the electrical continuity, or lack thereof, indicates whether the light bulb is functional or burned out. When a passenger vehicle <NUM> drives by the streetlight <NUM>, the driver's smartphone, W-Fi client <NUM>, may receive a spoofed beacon frame, probe response frame, or other management frame (e.g., <NUM> of <FIG>) from the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM>. In certain embodiments, Wi-Fi client <NUM> is not required to authenticate to, or associate with, the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of passive sensor <NUM> and the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) is not required to provide upstream network connectivity. In other embodiments, Wi-Fi client <NUM> cannot authenticate to, or associate with, the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> and the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) does not provide any upstream network connectivity. It is important to note that Wi-Fi client <NUM> has received, without awareness, sensor data in the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>).

Continuing, <FIG> shows an exemplary spoofed management frame <NUM> provided by the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> in accordance with one or more embodiments of the present invention. As shown, SSID subfield <NUM> may contain sensor data, in this instance, an indicator of whether the light bulb is functional or burned out. In the example, continuity may indicate the light bulb is functional and a lack of continuity may indicate the light bulb is burned out. Here, for purposes of illustration, we will assume that the sensor data indicates that the light bulb is burned out. The sensor data may be numeric or alphanumeric, explicit or encoded, and customized based on the type or kind of sensor and the type of sensed data it provides. Here, since the SSID is a textual field <NUM>, an alphanumeric representation of the sensor output, "BULB OUT", may be placed in SSID subfield <NUM>. One of ordinary skill in the art will recognize that passive sensor may include hardware and software, such as firmware that allows for the customizable presentation of sensor data based on a sensed physical property. In the example, the firmware may place the appropriate alphanumeric data corresponding to the binary continuity state of the light bulb in SSID subfield <NUM>. One of ordinary skill in the art will recognize that other fields may be used in accordance with one or more embodiments of the present invention.

Continuing, <FIG> shows a system <NUM> for passive sensor tracking with existing infrastructure in accordance with one or more embodiments of the present invention. After the driver's smartphone, Wi-Fi client <NUM>, receives the sensor data as part of the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame, the Wi-Fi client <NUM> may report the encounter with the Wi-Fi access point, typically as part of location services but Wi-Fi client <NUM> may transmit information relating to the encounter with Wi-Fi AP Database <NUM> or directly or indirectly to sensor tracking database <NUM>. While the information reported by Wi-Fi client <NUM> typically relates to unique identifying information of the Wi-Fi access point encountered, it includes certain information including, for example, the BSSID and the SSID of the Wi-Fi access point (e.g., <NUM>) or the dummy Wi-Fi Access Point (e.g., <NUM> of <FIG>) of passive sensor <NUM>. While the BSSID and SSID are used in this example, one of ordinary skill in the art will recognize that any fields or subfields, or combinations or portions thereof, may be used to convey sensor data. When a client (not shown) wishes to determine the state of a given passive sensor <NUM>, the client (not shown) may access sensor tracking database <NUM> through a standalone client application (not shown) or web-based portal <NUM> thereof. Using the unique identifying information of passive sensor <NUM>, the client (not shown) may find reports corresponding to the sensor <NUM> of interest. Then the client (not shown) may find the sensor data in the predetermined field used to store or encode the data, in this instance, the SSID field (e.g., <NUM> of <FIG>). In the example, the client (not shown) will see that the sensor data is "BULB OUT", indicating that the light bulb is burned out. In this way, a streetlight fixture, without a network connection of any kind may, through use of passive sensor <NUM>, transmit sensor data (e.g., <NUM> of <FIG>) using existing infrastructure, namely, the community of smartphones (e.g., Wi-Fi clients <NUM>) that happen to encounter the Wi-Fi access point (e.g., <NUM> of <FIG>) or the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) of passive sensor <NUM> and report those encounters.

In one or more embodiments of the present invention, a method of passive sensor tracking with existing infrastructure may include associating, in a sensor tracking database, unique identifying information of a Wi-Fi access point of a passive sensor with a physical property to be sensed by the passive sensor. The unique identifying information may be any information that uniquely identifies the Wi-Fi access point of the passive sensor and is reported by a Wi-Fi client that encounters the Wi-Fi access point, typically as part of location services, but potentially a direct or indirect report. The sensor data may be placed or encoded in one or more fields of the spoofed beacon frame, probe response frame, or other management frame transmitted by the Wi-Fi access point as part of Wi-Fi wireless network discovery. In certain embodiments, the Wi-Fi access point of the passive sensor may be a dummy Wi-Fi access point that does not allow the wireless device to authenticate to, or associate with, the dummy Wi-Fi access point and the dummy Wi-Fi access point does not provide upstream network connectivity.

In certain embodiments, the unique identifying information may be, for example, the BSSID of the Wi-Fi access point of the passive sensor. However, one of ordinary skill in the art will recognize that any field or subfield of the spoofed beacon frame, probe response frame, or other management frame may be used to uniquely identify the Wi-Fi access point, and by association the passive sensor, in accordance with one or more embodiments of the present invention. Notwithstanding the above, to avoid potential overlap or confusion, using the standardized BSSID that are guaranteed to be unique, may provide the simplest solution to uniquely identifying the Wi-Fi access point of the passive sensor.

The method may also include receiving, at the sensor tracking database, sensor data, comprising the physical property sensed by the passive sensor, placed or encoded in the spoofed beacon frame, probe response frame, or other management frame that the passive sensor transmits, as part of Wi-Fi wireless network discovery, to a wireless device that encounters the passive sensor. As noted above, the sensor data may be numeric or alphanumeric, explicit or encoded, and stored in any suitable field or subfield or combination or portions thereof of the spoofed beacon frame, probe response frame, or other management frame, provided it is a field or subfield that is reported by the Wi-Fi client that reports the encounter with the Wi-Fi access point of the passive sensor to a Wi-Fi AP Database or sensor tracking database. The wireless device may report, either directly or indirectly, the unique identifying information of the Wi-Fi access point of the passive sensor encountered and the sensor data encoded in the spoofed beacon frame, probe response frame, or other management frame to a Wi-Fi AP Database, typically as part of location services, or direct or indirect report to sensor tracking database.

In certain embodiments, the sensor data may be received by the sensor tracking database from the wireless device that encounters the passive sensor. In other embodiments, the sensor data may be received by the sensor tracking database from a Wi-Fi AP Database that receives the sensor data from the wireless device that encounters the passive sensor. The Wi-Fi AP Database may comprise a database managed by an original equipment manufacturer, an operating system developer, or a third-party software developer that compiles and makes information relating to reported Wi-Fi access points available to third-parties, typically to enhance location services, but potentially for other uses.

The wireless device may not be required to authenticate to, associate with, or establish a network connection with the Wi-Fi access point or the dummy Wi-Fi access point of the passive sensor. In addition, the wireless device, or user thereof, is not required to knowingly participate in the passive sensor tracking task. The method may optionally include disposing the passive sensor in a location where the physical property is to be sensed. The method may optionally include providing a user access to the sensed physical property of the passive sensor. In one or more embodiments of the present invention, a non-transitory computer readable medium comprising software instructions, when executed by a processor, may perform any of the above-noted methods.

In one or more embodiments of the present invention, a system (e.g., <NUM> of <FIG>) for passive sensor tracking with existing infrastructure may include a computing system (e.g., <NUM> of <FIG>), and a sensor tracking database (e.g., <NUM> of <FIG>), executing on the computing system (e.g., <NUM> of <FIG>), that associates unique identifying information of a Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of a passive sensor (e.g., <NUM> of <FIG>) with a physical property to be sensed by the passive sensor (e.g., <NUM> of <FIG>). The Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) may transmit a spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>) that comprises sensor data (e.g., <NUM> of <FIG>) as part of Wi-Fi wireless network discovery. The unique identifying information may be any information that uniquely identifies the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>) and is reported by a Wi-Fi client (e.g., <NUM> of <FIG>) that encounters the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>), typically, but not limited to, as part of location services. The sensor data (e.g., <NUM> of <FIG>) may be placed or encoded in one or more fields of the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>) transmitted by the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) as part of Wi-Fi wireless network discovery. In certain embodiments, the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>) may be a dummy Wi-Fi access point (e.g., <NUM> of <FIG>) that does not allow the wireless device (e.g., <NUM> of <FIG>) to authenticate to, or associate with, the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) and the dummy Wi-Fi access point (e.g., <NUM> of <FIG>) does not provide upstream network connectivity.

In certain embodiments, the unique identifying information may be, for example, the BSSID (e.g., <NUM> of <FIG>) of the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>). However, one of ordinary skill in the art will recognize that any field or subfield of the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>) that is reported may be used to uniquely identify the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>), and by association the passive sensor, in accordance with one or more embodiments of the present invention. Notwithstanding the above, to avoid potential overlap or confusion, using the standardized BSSID (e.g., <NUM> of <FIG>) that are guaranteed to be unique, may provide the simplest solution to uniquely identifying the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>).

The sensor tracking database (e.g., <NUM> of <FIG>) may receive sensor data (e.g., <NUM> of <FIG>), comprising the physical property sensed by the passive sensor (e.g., <NUM> of <FIG>), placed or encoded in the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>) that the passive sensor (e.g., <NUM> of <FIG>) transmits, as part of Wi-Fi wireless network discovery, to a wireless device (e.g., <NUM> of <FIG>) that encounters the passive sensor (e.g., <NUM> of <FIG>). As noted above, the sensor data (e.g., <NUM> of <FIG>) may be numeric or alphanumeric, explicit or encoded, and stored in any suitable field or subfield or combination or portions thereof of the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>), provided it is a field or subfield that is reported by the Wi-Fi client (e.g., <NUM> of <FIG>) that reports the encounter with the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>) directly or indirectly to a Wi-Fi AP Database (e.g., <NUM> of <FIG>) or sensor tracking database (e.g., <NUM> of <FIG>). The wireless device (e.g., <NUM> of <FIG>) may report, either directly or indirectly, the unique identifying information of the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>) encountered and the sensor data (e.g., <NUM> of <FIG>) in the spoofed beacon frame (e.g., <NUM> of <FIG>), probe response frame (e.g., <NUM> of <FIG>), or other management frame (e.g., <NUM> of <FIG>) to a Wi-Fi AP Database (e.g., <NUM> of <FIG>), typically as part of location services, or to a sensor tracking database (e.g., <NUM> of <FIG>).

In certain embodiments, the sensor data (e.g., <NUM> of <FIG>) may be received by the sensor tracking database (e.g., <NUM> of <FIG>) from the wireless device (e.g., <NUM> of <FIG>) that encounters the passive sensor (e.g., <NUM> of <FIG>). In other embodiments, the sensor data (e.g., <NUM> of <FIG>) may be received by the sensor tracking database (e.g., <NUM> of <FIG>) from a Wi-Fi AP Database (e.g., <NUM> of <FIG>) that receives the sensor data (e.g., <NUM> of <FIG>) from the wireless device (e.g., <NUM> of <FIG>) that encounters the passive sensor (e.g., <NUM> of <FIG>). The Wi-Fi AP Database (e.g., <NUM> of <FIG>) may comprise a database managed by an original equipment manufacturer, an operating system developer, or a third-party software developer that compiles and makes information relating to reported Wi-Fi access points available to third-parties, typically to enhance location services, but potentially for other reasons as well.

The wireless device (e.g., <NUM> of <FIG>) may not be required to authenticate to, associate with, or establish a network connection with the Wi-Fi access point (e.g., <NUM>/<NUM> of <FIG>) of the passive sensor (e.g., <NUM> of <FIG>). In addition, the wireless device (e.g., <NUM> of <FIG>), or user (not shown) thereof, are not required to knowingly participate in the passive sensor tracking task. The system (e.g., <NUM> of <FIG>) may optionally include the passive sensor (e.g., <NUM> of <FIG>) disposed in a location where the physical property is to be sensed. The system (e.g., <NUM> of <FIG>) may optionally include providing a user (not shown) access to the sensed physical property of the passive sensor (e.g., <NUM> of <FIG>) via the sensor tracking database (e.g., <NUM> of <FIG>) or a client portal (e.g., <NUM> of <FIG>) thereof.

<FIG> shows a dummy Wi-Fi access point <NUM> of a passive sensor (e.g., <NUM> of <FIG>) in accordance with one or more embodiments of the present invention. Dummy Wi-Fi access point <NUM> may spoof certain operations of a bona fide Wi-Fi access point (e.g., <NUM> of <FIG>) by participating in at least part of the Wi-Fi wireless network discovery protocol by transmitting spoofed beacon frames, probe response frames, or other management frames that comprise sensor data as discussed above, but is not required to participate in authentication, association, or data transfer. As such, dummy Wi-Fi access point <NUM> may include only those features necessary to spoof a bona fide Wi-Fi access point and transmit the sensor data in spoofed beacon frames, probe response frames, or other management frames, without necessarily requiring more.

The reduced complexity of the device allows for greater integration, reduces power, and minimizes the mechanical footprint required for the device. Similar to a conventional Wi-Fi access point, the primary computational engine of the device may be the integrated processing core <NUM> that performs the computation and processing tasks, such as, for example a MIPS32® <NUM>® Core. One of ordinary skill in the art will recognize that the MIPS component referenced is merely exemplary and other integrated cores may be used in accordance with one or more embodiments of the present invention. Firmware <NUM>, that may be flashable, may store the software instructions executed by the integrated processing core <NUM>. In addition, Static Random-Access Memory ("SRAM") <NUM> may store settings that are loaded at run time or other persistent data. When dummy Wi-Fi access point <NUM> broadcasts spoofed beacon frame, probe response frame, or other management frames, integrated processing core <NUM> may transmit the data to the radio interface <NUM> for putting the data on the antenna (not shown). Other aspects of a conventional Wi-Fi access point, including, but not limited to, a flash interface <NUM>, a <NUM>/<NUM>/<NUM> MAC interface <NUM>, an I<NUM>C interface, a Dynamic Random Access Memory ("DRAM") interface <NUM>, and a Universal Asynchronous Receiver/Transmitter ("UART") interface (not shown) among others, may not be included to reduce the complexity of the feature set, reduce power consumption, and minimize the mechanical footprint of the device.

As discussed above, a passive sensor (e.g., <NUM> of <FIG>) may include a sensor portion (e.g., <NUM> of <FIG>) that senses a physical property, a sensor interface (e.g., <NUM> of <FIG>) that receives the output of the sensor portion (e.g., <NUM> of <FIG>) and conveys the sensor data to the integrated processing core <NUM> for inclusion in the spoofed beacon frame, probe response, or other management frame. The sensor interface (e.g., <NUM> of <FIG>) may convey the sensor data to the integrated processing core <NUM> via General Purpose Inputs/Outputs ("GPIOs") or any other supported means of conveying that data. The firmware <NUM> may include some or all of the software that governs the operation of the various components of the dummy Wi-Fi access point <NUM>. While the role of firmware <NUM> in conventional Wi-Fi access points (e.g., <NUM>) is well known to those of ordinary skill in the art, in passive sensor (e.g., <NUM>) applications, firmware <NUM> may coordinate the input of the sensor data (not shown) provided by the sensor interface (e.g., <NUM>) of the passive sensor (e.g., <NUM>) and may construct the spoofed management frames (e.g., <NUM> of <FIG>) that comprises sensor data (not shown).

Advantages of one or more embodiments of the present invention may include one or more of the following:
In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure allows for passively tracking moveable assets by one or more potentially unrelated wireless devices that are in-range of assets broadcasting Wi-Fi signals even though the wireless device, or user thereof, may not even know they are participating in the asset tracking task. In this way, every smartphone in the vicinity of an asset that is desired to be tracked may, anonymously, and without awareness, participate in the asset tracking task.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure leverage already existing devices, systems, and networks to passively track the location of assets without requiring the asset itself to have any connectivity to the Internet or other network connection.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure uses one or more Wi-Fi access points, that do not require connectivity to any particular network, to identify one or more assets in the field using Wi-Fi wireless network discovery and Wi-Fi access point reporting features of modern smartphones and location services to passively identify the location of the one or more assets. The moveable assets may be passively tracked by one or more wireless devices that may be independent and unrelated whenever any one or more of the wireless devices merely come into range of an asset associated with a Wi-Fi access point broadcasting Wi-Fi signals, without any intent or awareness on the part of the wireless device, or user thereof, that they are participating in the asset tracking task due to the nature of the Wi-Fi wireless network discovery protocol.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure leverages existing infrastructure inherent in smartphones, operating systems, and software applications to report their location as well as the unique identifying information of Wi-Fi access points they encounter for improving the accuracy of location-based services for the asset tracking task without their awareness.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure uses the Wi-Fi wireless network discovery protocol as well as the Wi-Fi access point reporting feature of smartphones to passively track assets associated with Wi-Fi access points by one or more wireless devices without requiring that the wireless devices associate with any particular Wi-Fi access point, using publicly accessibly Wi-Fi signals, and in passive scanning applications, completely anonymously with respect to the asset tracking task.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure, a Wi-Fi access point associated with an asset does not require any connectivity to the Internet or any other network connection and does not require a GPS receiver, relying instead on the one or more wireless devices to report the time, date, and relative location of the in-range Wi-Fi access point associated with the asset.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure, an asset tracking database receives unique information identifying and information relating to the location of one or more Wi-Fi access points received directly or indirectly from one or more wireless devices or a Wi-Fi AP Database. The location of the asset may be tracked in the asset tracking database by the location of the Wi-Fi access point.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure may use a Wi-Fi access point that allows for the assignment of alternative meanings to various parts of the beacon frame or probe response corresponding to attributes of the Wi-Fi access point or asset physically and logically associated with it.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure reduces theft by providing a trackable asset without conventional asset tracking hardware or software systems. If the perpetrator of the theft moves a trackable asset within range of any one or more wireless devices, the discovery of the Wi-Fi access point will be reported, and the asset tracking database will be able to locate the associated asset without the perpetrator knowing that the asset has been tracked.

In one or more embodiments of the present invention, a method and system for passive asset tracking with existing infrastructure substantially reduces the complexity and cost associated with deploying a comprehensive asset tracking system. As opposed to conventional asset tracking systems, one or more wireless devices, which may be completely independent of and unrelated to the asset tracking task, serve as the tracking infrastructure.

Claim 1:
A method of passive sensor (<NUM>) tracking with existing infrastructure comprising:
associating, in a sensor tracking database (<NUM>), unique identifying information of a Wi-Fi access point (<NUM>) of a passive sensor (<NUM>) with a physical property to be sensed by the passive sensor (<NUM>), wherein the Wi-Fi access point (<NUM>) transmits sensor data in a field of a spoofed beacon frame, probe response frame, or other management frame (<NUM>) as part of Wi-Fi wireless network discovery; wherein the field is a field that is reported by a wireless device that encounters the Wi-Fi access point (<NUM>) as part of location services; and
receiving, at the sensor tracking database (<NUM>) sensor data, comprising the physical property sensed by the passive sensor (<NUM>), in the spoofed beacon frame, probe response frame, or other management frame (<NUM>) transmitted by the Wi-Fi access point (<NUM>), as part of Wi-Fi wireless network discovery, to a wireless device (<NUM>) that encounters the passive sensor (<NUM>),
wherein the wireless device (<NUM>) reports, either directly or indirectly, the unique identifying information of the Wi-Fi access point (<NUM>) encountered and the sensor data in the spoofed beacon frame, probe response frame, or other management frame (<NUM>) to a Wi-Fi AP Database (<NUM>) that tracks reported Wi-Fi access points as part of location services,
wherein the wireless device (<NUM>) is not required to authenticate to, associate with, or establish a network connection with the Wi-Fi access point (<NUM>) of the passive sensor (<NUM>), and
wherein the wireless device (<NUM>), or user thereof, is not required to knowingly participate in the passive sensor (<NUM>) tracking task.