This application claims priority to U.S. Provisional Application No. 60/481,667, filed Nov. 19, 2003, the entirety of which is incorporated herein by reference.
Wireless local area network (WLAN) connectivity, such as IEEE 802.11 technology (also known as WiFi™), has proliferated into the consumer home and enterprise environment. Many enterprises rely on WLAN connectivity in place of traditional wired LANs. Moreover, there has been a recent trend to incorporate WLAN capability into other radio communication devices, such as mobile cell phones. A mobile cell phone with WLAN capability allows a user to have connectivity in both a wide area network (WAN) environment through the cell phone infrastructure as well as wireless LAN connectivity.
Techniques are being developed to locate devices operating in the wireless LANs. This has utility in maintaining the security of the wireless LAN, particularly in a corporate enterprise environment. In fact, these location techniques have much greater accuracy than the location techniques available on cell phone networks, particularly when the cell phone device goes into an indoor environment.
It would be desirable to exploit the location capabilities of wireless LANs in locating a device that has both wireless WAN and wireless LAN communication capability.
Briefly, techniques are provided that enable accurate location tracking of devices having both wireless WAN and wireless LAN capability. A device with this dual communication capability may be triggered to initiate a wireless LAN location procedure in response to receiving a wireless WAN signal. The request for initiating the location process may be a user of the device itself, or any third party desiring knowledge about the location of the device. This process exploits the advantages of the wireless LAN location capabilities to use the wireless LAN link for location determination which may be more accurate than wireless WAN and/or global positioning system (GPS) location techniques. Any location technique useful in a wireless LAN environment may be employed. The system and method described herein are useful to locate any individual or object that is carrying or is tagged with a device having wireless WAN and wireless LAN connectivity.
Other objects and advantages of the present invention will become more readily apparent when reference is made to the following description in conjunction with the accompanying drawings.
Referring first to
The integrated wireless WAN/LAN location process uses the relatively long-range communication capabilities of the wireless WAN to contact the device, and then uses the relatively short-range communication capabilities to more accurately determine the physical location of the device. The location information may be delivered to a variety of different types of parties that either request or may be interested in the location information. However, according one embodiment described hereinafter, a device having wireless VoIP communication capabilities may initiate the wireless LAN location procedure without necessarily resorting to the wireless WAN system.
The wireless WAN portion of the system includes a wireless WAN operator control center 40 that connects to a plurality of wireless WAN base stations, which in this example two are shown 42(1) and 42(2). Each base station 42(1) and 42(2) connects to a wireless WAN tower 44(1) and 44(2), respectively, that transmits and receives wireless WAN signals to and from wireless WAN capable devices, including device 10.
As appreciated by those with ordinary skill in the art, a wireless WAN system can communicate with devices over relatively large distances between the base station and the device, when the device is located both indoor and outdoors. In this sense, it is a relatively long-range communication system as compared to a wireless LAN system in which a device can communicate over relatively smaller distances between and AP and a device. A unique aspect of the method described herein is that the WAN system can be exploited to contact a device to be located that is otherwise in an area where wireless WAN or GPS location techniques are not as accurate or perhaps not possible. Once contacted, the WAN system can send a signal to the device that causes the device to initiate a wireless LAN location procedure with respect to a wireless LAN in proximity to the device.
Another component of the system is a supervisory location server 60 that performs security and higher level management 64 in connection with the integrated wireless WAN/LAN location process and may optionally perform the location computations 32 associated with the wireless LAN location process. The supervisory location server 60 may cooperate with a user directory 66 that stores security, identifier and related information for the wireless WAN/LAN capable devices for which the location services is to be provided. The user directory 66 stores identifier and authentication information about each of the devices that can be located, and also about each of the parties a user of the device may designate as authorized to receive location information about the device. This information is used to authenticate a device and a party requesting location information about the device to provide adequate security and privacy with respect to the location of the device.
There are many ways to initiate the location process. According to one method, shown in
The flow charts shown in
The process of
In the device 10, there is a location session software process or other functionality that processes the wireless LAN location initiate message and in response causes the device 10 in step 140 to initiate a wireless LAN location procedure with a WLAN location server, such as server 30. When the device 10 receives the wireless LAN location initiate message from the wireless WAN operator equipment, it may already be associated with an AP. If not, it will attempt to associate by sending a Beacon frame or a request-to-send (RTS) frame or other suitable 802.11 frame to a WLAN AP. In any event, once associated with an AP, in step 140, the device 10 sends a location start session message (including a verification identifier) addressed to WLAN location server 30 (or any other WLAN location server identified in the message related to the device 10 in step 130) via an AP. When the WLAN location server 30 receives the location start session message via the AP from the device 10, further authentication may be conducted by exchanging information with the supervisory location server 60 for verification against data in the user directory 66 based on name, cell phone number, MMS address, etc. to be sure the device 10 is authenticated before initiating the location process.
The WLAN location server 30 starts a location process in step 150 by sending location set-up messages to the device 10 and to sensors 20(1)-20(4) that will participate in the location procedure. In response to receiving the location set-up messages, the sensors 20(1) to 20(4) prepare for the WLAN location procedure.
Step 160 represents execution of the WLAN location procedure. The types of signals transmitted, data captured, measurements made and computations performed in step 160 depend on the specific type of WLAN location procedure employed. Any procedure suitable for use in the WLAN environment may be employed in connection with the processes described herein. Some WLAN location procedures involve collecting data at one or more sensors 20(1) to 20(4) associated with the transmission of one or more signals by the device 10 (and optionally transmission of signals by one of the sensors at a corresponding known location). The sensors 20(1) to 20(4) send collected data to the WLAN location server 30 that executes a location computation in step 170 to compute the location of the device 10. In step 180, the location server 30 then sends location information to the requester, either directly or through the supervisory location server to the requester, via an email message. Alternatively, the location information may be conveyed to the requester through the wireless WAN operator control equipment 40 in the form of an email, voice message, call back number, web page link to a map view, etc. The location information may take the form of coordinates, street address, building room location, as well as graphical information showing the three-dimensional location of a device within a building, etc.
The advantage of the wireless LAN location process is that it provides higher resolution location accuracy of the device that is to be located, and also in many cases, locates the device in conditions where a wireless WAN location process (GPS, and other known wireless WAN location techniques) could not locate the device.
Upon completion of the location computation, the location server 30 may send a message that instructs the device 10 to terminate the WLAN connection in order to save power on the device 10. However, if the device 10 is using the WLAN connection for voice or data communications, it may maintain the link for this purpose and the location server 30 may continue tracking the location of the device based on transmissions back and forth with an AP using data captured at the sensors in proximity to the device 10.
In the event that the device 10 has VoIP capability via a wireless LAN, the process shown in
While the foregoing description of
Referring to
The wireless LAN location process used in conjunction with the process described herein may be any heretofore known or hereinafter developed methodology and system for locating devices operating in a wireless LAN environment. Known location techniques employ time of arrival (TOA), time difference of arrival (TDOA), and received signal strength with respect to one or more signals transmitted by the device to be located. For a TDOA-based location system, see, for example, commonly assigned and co-pending U.S. application Ser. No. 10/409,563, filed Apr. 8, 2003, and entitled “System and Method for Locating Wireless Devices in an Unsynchronized Wireless Environment,” the entirety of which is incorporated herein by reference. Examples of location processes that operate on received signal strength information are described, for example, in U.S. Pat. No. 6,674,403 B2 and International Patent Publication No. WO 02/054813A1, which are incorporated herein by reference. The details of these location procedures are not described herein, but may be found in the aforementioned and other documents describing these techniques.
To summarize, a method is provided for determining the physical location of a device that has both wireless wide area network (WAN) communication capability and wireless local area network (LAN) communication capability, comprising steps of receiving a signal at the device from wireless WAN equipment that causes the device to initiate a wireless LAN location process; and executing the wireless LAN location process to determine the physical location of the device. Said another way, a method is provided for determining the physical location of a device that has both wireless relatively long-range communication capability and wireless relatively short-range communication capability, the method comprising steps of: receiving a relatively long-range communication signal at the device from wireless equipment that causes the device to initiate a wireless short-range location process; and executing the wireless short-range location process to determine the physical location of the device.
From the perspective of the steps performed in the device itself, the method generally comprises steps of receiving a signal from wireless WAN equipment that is intended to initiate a location procedure to locate the device; and initiating a wireless LAN location process in response to receiving the signal.
In addition, in the context of the steps performed in the device itself, a processor readable medium is provided that is encoded with instructions that, when executed by a processor, perform steps of processing a signal received from wireless WAN equipment that is intended to initiate a location procedure to locate a device that receives the signal; and initiating a wireless LAN location process in response to receiving the signal. Similarly, a processor readable medium is provided that is encoded with instructions that, when executed by a processor, perform steps of generating a wireless signal for transmission from the device, wherein the wireless signal includes information that indicates a location procedure is to be performed with respect to the device; and initiating a wireless LAN location process to determine the physical location of the device.
Moreover, a method is provided for determining the physical location of a device that has both wireless wide area network (WAN) communication capability and wireless local area network (LAN) communication capability, comprising steps of: transmitting a wireless signal from the device, wherein the wireless signal includes information that indicates a location procedure is to be performed with respect to the device; and executing a wireless LAN location process to determine the physical location of the device.
Further still, a wireless radio communication device is provided comprising a radio receiver that receives wireless wide area network (WAN) signals; a radio transceiver that transmits and receives wireless local area network (LAN) signals; and a processor coupled to the radio receiver and to the radio transceiver that processes a signal received by the radio receiver from wireless WAN equipment that is intended to initiate a location procedure to enable the device to be located, and initiating a wireless LAN location process in response to receiving the signal.
From the perspective of a server that manages or participates in a process for locating a device that has both wireless wide area network (WAN) communication capability and wireless local area network (LAN) communication capability, the method comprising steps of: receiving from a party a request to locate the device; verifying the party making the request and the device to be located; sending a signal to wireless WAN equipment that caused the wireless WAN equipment to transmit a signal to the device the causes the device to initiate a wireless LAN location process; and receiving location information determined from the wireless LAN location process and delivering the location information to the party.
The above description is intended by way of example only.
Number | Date | Country | |
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60481667 | Nov 2003 | US |