Communications: directive radio wave systems and devices (e.g. – Directive – Position indicating
Reexamination Certificate
2002-09-05
2004-01-06
Tarcza, Thomas H. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Position indicating
C342S453000, C342S465000
Reexamination Certificate
active
06674403
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of real-time position detection and motion tracking of wireless communications devices.
BACKGROUND
Communications with wireless devices has quickly become a ubiquitous part of modern life. Such wireless devices can take any of a number of forms. As examples, wireless devices may include cellular telephones and pagers, as well as various types of Internet, Web, or other network enabled devices, such as personal digital assistants (PDAs). Rapid growth has come in the mobile telephone realm and in the realm of other personal and business computing devices. The number of cellular telephone customers, for example, has grown exponentially over the past few years, so too has the number of wireless personal and business computing devices. Any of these network enabled devices may include Internet or Web functionality. Generally, a wireless device configured for transmitting, receiving, accessing, or exchanging data via a network may be referred to as a “mobile device” and communications between mobile devices may be referred to as “wireless communications”.
As part of the technical development of the networks to meet the demand for mobile communications, carriers have migrated from an analog-based technology to several digital transport technologies, wherein digital data is “packetized” and transmitted across digital networks. Newer versions of digital wireless communication networks support a variety of data communication services that are intended to extend the common data communication capabilities of the wired domain to the wireless mobile domain.
The current trend in the cellular realm is toward the Third Generation of Wireless Telephony (3G) networks (e.g., 3G-1x networks). The 3RD Generation Partnership Project 2 (3GPP2) standard entitled Wireless IP Network Standard, 3GPP2 P.S0001-A, Version 3.0.0, © 3GPP2, version date Jul. 16, 2001 (the “3GPP2 Standard”, a.k.a. the IS-835 Standard”) codifies the use of mobile IP in a 3G-1x packet data network, also referred to as a code division multiple access (CDMA) or CMDA2000-1x packet data network.
In the personal and business realm, where wireless communication can take place in a localized area via local communications network, the IEEE 802.11 standard is prevalent. A localized area may be a building, an area within a building, an area comprising several buildings, outdoor areas, or a combination of indoor and outdoor areas. Most modern means of position detection and motion tracking techniques of an object either involve: 1) signal timing analysis, such as time (difference) of arrival (TOA or TDOA) based measurements, such as global positioning systems (GPS); 2) signal frequency shift analysis, such as RADAR; 3) the use of predetermined signal beacons for active or passive detection, such as interrupting a beam of light upon entry or exit of a space; or 4) having a network of receivers that detect presence of a mobile beacon signal traveling through a space, such as infrared transmitters on PDAs or cellular telephones within reach of local cellular tower, or triangulation via a combination of these or related methods.
Most of these techniques are application-specific to the task of measuring position and often serve no other function, except in the case of a mobile phone as noted above, where the location of a cellular phone can be detected at a coarse scale of hundreds of feet, concluding it is in the vicinity of a given tower. Some of these techniques are unavailable in certain spaces such as the use of GPS indoors or underground, or are impractical because of interference, signal multi-path effects, or because the optimal speed profiles for the objects being tracked (such as RADAR) do not match the motive behavior of the objects. Lastly, merely the deployment of a network of sensors as described above for position detection of a mobile device could be prohibitively expensive and impractical for this single function.
In some settings, detection and location within a defined local area is performed using a local area network (LAN) comprised of a set of “access points” (APs). The APs are communication ports for wireless devices, wherein the communication occurs across an “air link” between the wireless device and the APs. That is, APs pass messages received from the wireless device across the LAN to other servers, computers, applications, subsystems or systems, as appropriate. The APs are bi-directional, so also configured to transmit to the wireless device. Typically, the APs are coupled to one or more network servers, which manage the message traffic flow. Application servers may be coupled to or accessed via the network servers, to provide data or typical application functionality to the wireless device.
In such systems, the process of defining the local area (e.g., room layouts, ground layouts, and so on) to the network is often referred to as “training” the area or system. The area is divided up into spaces, which wireless devices transition between as they migrate through the trained area. The location and detection within the trained area is typically determined as a function of the signal strength from the wireless device with respect to one or more APs. The APs are configured to determine the signal strength and pass it on to a back-end subsystem for processing.
Location and detection are typically determined as a function of received signal strength indicator (RSSI) values obtained from the communications between the wireless device and the LAN. As a general rule, the higher the signal strength, the closer a transmitting wireless device is presumed to be to an AP. Changes in the signal strength as the wireless device moves about the trained area allows for tracking. If there are at least three APs that receive the signals from the wireless device, trilateration can be used to determine the location of the device within the trained area. Trilateration is a method of determining the position of the wireless device as a function of the lengths between the wireless device and each of the APs.
Trilateration calculations are performed by the wireless device using the RSSI data, which must be configured with appropriate software (e.g., a client-side module) to accomplish such tasks. As a result, the demands on the wireless device are increased. Furthermore, while detection and tracking are desired for substantially all wireless devices within the trained area, it is much more difficult to achieve, since the many types of wireless devices may all have different configurations.
SUMMARY OF THE INVENTION
A system and method are provided that allow for network-based position detection and tracking of a wireless mobile (or client) device within a defined space, e.g., a mobile device detection and tracking system. Preferably, the mobile device needs no special client-side configuration, modules, or programs to be detected and tracked, since detection and tracking are preformed on the network side of the interface. The availability of applications and access to data may be selectively provided or inhibited as a function of the location of the mobile device and an identity of the mobile device or its user, or both. The present inventive approach to real-time position detection or motion tracking can be applied to outdoor wide-area communications media, such as cellular or pager networks or indoor/outdoor to wireless local area networks (LAN) and communications such as IEEE 802.11 or “Bluetooth”.
The mobile device may be any known portable or transportable device configured for wireless communications, such as a mobile telephone, personal digital assistant (PDA), pager, e-mail device, laptop, or any Web enabled device. Many of such devices may be handheld devices, but other wireless devices that are not of such a compact size could also be detected and tracked. As wireless devices, the mobile devices are configured to communicate with a network through a wireless interface.
The mobile device detection and tracking system includes a network, a plurality of detectors (e.g., acc
Chery Yonald
Gray Matthew K.
Peden, II Jeffrey J.
McDermott & Will & Emery
Mull Fred H.
Newbury Networks, Inc.
Tarcza Thomas H.
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