Abstract:
A mobile device in a wireless communication network is provided with a positioner configured to determine geographic position information related to the device. The mobile device is further provided with a transceiver assigned a unique mobile number by a wireless communication system in which the device operates, and which is communicatively coupled to the positioner. The transceiver is configured to receive position requests directed to the mobile number and to transmit the position information in response to the position requests. In one implementation, a transceiver within a particular device is activated when a call is placed through the wireless communication system to the mobile number associated with the device. The location transceiver is configured to obtain position information from the positioner, and to continuously transmit the position information to the network node, as soon as the location transceiver is activated. The network node is configured to route the position information to a location control center. At the location control center, a map of the area proximate the location of the device is generated, and the location of the device is identified on the map, based on the received position information. If the positioner is unable to determine the position information for the device when requested, the transceiver is configured to continuously transmit a tone in response to the position request.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates generally to locating a portable electronic device, where the device is lost or the position of the device is otherwise unknown.  
           [0003]    2. Background  
           [0004]    The number and variety of portable electronic devices is growing. For example, devices such as PDAs, laptop computers, palm computers, cellular phones, and portable MP 3  players are very popular. As the popularity and capability of these devices grows, users of the devices are becoming more and more dependent on them. For example, a PDA may contain all of a user&#39;s business contact information. A laptop may contain important presentation material, or even important company secrets. Even an MP 3  player that stores a user&#39;s favorite songs can represent an investment of the user&#39;s time and money. The user, or the user&#39;s company, may be inconvenienced or even compromised if such devices are lost or stolen. Typically, however, the user has little recourse in trying to recover the device.  
           [0005]    For example, a laptop computer may contain valuable trade secrets. But if the laptop were to be stolen, the users only recourse is to report the theft to the police. The police have limited resources, however, and recovering a stolen laptop may not receive the attention that the user would like. The user could hire a private investigator to try and recover the device, and if the trade secrets are valuable enough, then the cost of such an option may be worthwhile. But in the case of a PDA or other portable electronic device, such an option is probably not worth the cost. This does not mean, however, that loss of such devices would not have a large impact on the user.  
         SUMMARY OF THE INVENTION  
         [0006]    In accordance with the present invention, a mobile device, which is any device capable of being transported between different geographic locations, in a wireless communication network is provided with a positioner configured to determine geographic position information related to the device. The mobile device is further provided with a transceiver assigned a unique mobile number by a wireless communication system in which the device operates, and which is communicatively coupled to the positioner. The transceiver is configured to receive position requests directed to the mobile number and to transmit the position information in response to the position requests.  
           [0007]    In one implementation, a transceiver within a particular device is activated when a call is placed through the wireless communication system to the mobile number associated with the device. The location transceiver is configured to obtain position information from the positioner, and to continuously transmit the position information to the network node, as soon as the location transceiver is activated. The network node is configured to route the position information to a location control center. At the location control center, a map of the area proximate the location of the device is generated, and the location of the device is identified on the map, based on the received position information. If for some reason the positioner is unable to determine the position information for the device when requested, the transceiver may be configured to continuously transmit a tone in response to the position request.  
           [0008]    Other aspects, advantages and novel features of the invention will become apparent from the following Detailed Description of Preferred Embodiments, when considered in conjunction with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The drawings illustrate both the design and utility of preferred embodiments of the invention, wherein:  
         [0010]    [0010]FIG. 1 is a simplified block diagram illustrating a device configured to include a positioner and a transceiver in accordance with one embodiment of the invention.  
         [0011]    [0011]FIG. 2 is a simplified block diagram illustrating a wireless communication system configured in accordance with one embodiment of the invention and in which the device of FIG. 1 is configured to operate.  
         [0012]    [0012]FIG. 3 is a simplified block diagram illustrating a paging system configured in accordance with one embodiment of the invention and in which the device of FIG. 1 is configured to operate.  
         [0013]    [0013]FIG. 4 is a simplified block diagram illustrating further embodiments of the device in FIG. 1.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    [0014]FIG. 1 illustrates a device  100 , in this case a laptop computer, configured in accordance with one embodiment of the invention. Device  100  is typically a portable electronic device, but as will be apparent, device  100  is not limited to portable electronic devices. Device  100  includes a positioner  104  and a transceiver  106  that are configured to allow device  100  to be located when, for example, it is lost or stolen. In one embodiment, transceiver  104  and positioner  106  are combined in a single device  102 , such as, for example, an integrated circuit that combines circuitry adapted to perform the functions of positioner  104  and transceiver  106 . Positioner  104  is configured to acquire position information for device  100  and typically comprises a GPS receiver. Therefore, the position information will typically comprise the latitude and longitude coordinates of device  100 .  
         [0015]    A GPS receiver works by determining the position of at least three satellites in radio communication with the GPS receiver. The GPS comprises 24 satellites in all so that at least four of them are above the horizon for any given point on earth at any given time. To determine the satellite positions, a GPS receiver typically stores an almanac containing the positions of all 24 satellites. Once the GPS receiver has located the satellites, it uses the radio transmissions therefrom to determine the distance between the satellites and the GPS receiver by measuring the time it takes for the transmission to reach the receiver. Once the GPS receiver has this “transmission time” for each satellite, it can determine the distances to the satellites because radio transmissions travel at a known rate. Therefore, the transmission time multiplied by the known rate will provide the distance to a satellite. Combing the position and distance information for at least three satellites provides the latitude and longitude position of the receiver. If a fourth satellite is added, altitude can be determined as well.  
         [0016]    Positioner  104  is capable of communicating the position information to transceiver  106 . The position information may be communicated using standard protocols such as standard GPS communication protocols. Alternatively, if required, the position information can be communicated using a proprietary protocol developed for a specific implementation. Transceiver  106  includes a receiver, configured to receive position information requests, and a transmitter, configured to transmit the position information in response to such a request. In a typical embodiment, transceiver  106  is a radio transceiver. In which case, transceiver  106  will include an antenna port  108  coupled to an antenna  110 . Antenna  110  is configured to receive radio signals containing position requests and couple them to the receiver portion of transceiver  106  through port  108 . Antenna  110  is also configured to transmit radio signals containing the position information that are coupled from the transmitter portion of transceiver  106  to antenna  110  through port  108 .  
         [0017]    Ideally, positioner  104 , transceiver  106 , and antenna  110 , if required, are physical small and therefore the constraints on where they are positioned within device  100  are minimal. In this case, a main concern will be adequate RF performance in terms of sensitivity and transmission power of the antenna-transceiver combination. RF performance will vary for different combinations of antenna  110 , devices  100 , and the position of antenna  110  within device  100 . Therefore, the exact construction and position of antenna  110  within device  100  will be dependent on the requirement of each particular implementation.  
         [0018]    As will be seen, transceiver  106  is not limited to radio transceivers. Where transceiver  106  is a radio transceiver, however, a wireless communication system such as system  200  in FIG. 2 is used to locate device  100 . Wireless communication system  200  includes a plurality of mobile devices  202 , a Base Station Subsystem (BSS)  204 , and a Network Switching Subsystem (NSS)  210 . Mobile devices  202  are assigned a mobile number within system  200  and are generally configured to communicate voice and/or data over a wireless communication or air interface  222 . BSS  204  interfaces with mobile devices  202  to manage radio transmission paths between mobile devices  202  and NSS  210 . In turn, NSS  210  manages system switching functions with public networks  218  such as the PSTN or the ISDN.  
         [0019]    BSS  204  is comprised of multiple Base Transceiver Stations (BTS)  206  and at least one Base Station Controller (BSC)  208 . A BTS  206  is usually at the center of a “cell” and consists of one or more radio transceivers with an antenna. BTS  206  establishes radio links and handles radio communication over air interface  222  with mobile devices  202  within the “cell.” BSC  208  manages multiple BTSs  206  including the allocation and management of radio channels and the control and handover of communications between its transceivers.  
         [0020]    Air interface  222  comprises a range of frequencies in the RF spectrum. This range is then divided into a plurality of channels. Typically, each mobile device  202  is assigned two channels that are separated by some fixed frequency. One channel, the forward channel, carries transmission from a BTS  206  to a mobile device  202 . The second channel, the reverse channel, carries transmissions from a mobile device  202  to a BTS  206 . Unless otherwise specified, the term radio channel as used in this specification refers to the forward and reverse channels in combination.  
         [0021]    BSC  208  communicates with NSS  210 . A Mobile Switching Center (MSC)  212  is the primary component of NSS  210 . MSC  212  manages communications between mobile devices  202  and between mobile devices  202  and public network  218 . In addition, MSC  212  typically interfaces with several databases  214  to manage communication and switching functions. For example, MSC  212  may interface with a Home Location Register (HLR) that contains details on each mobile device  202  residing within the area served by the mobile switching center. There may also be a Visitor Location Register (VLR) that temporarily stores data about roaming mobile devices  202  within a coverage area of a particular MSC  212 . An Equipment Identity Register (EIR) that contains a list of mobile devices  202  may also be included. The EIR may also contain a list of equipment that has been lost or stolen allowing identification of attempts to use such equipment. There may also be an Authorization Center (AuC) that stores authentication and encryption data parameters that verify s mobile device user&#39;s identity.  
         [0022]    To the extent that the following examples refer to wireless communication system  200 , it is by way of example only, and is not intended to limit the use of the invention. Further, those skilled in the art will understand that there are many variations in wireless communication system architectures including variations in the communication protocols used for the various communication links within such systems. It will be apparent that the invention will work equally well with all possible architectures and all possible communication protocols. In fact, it is preferable that transceiver  106  be designed to implement multiple protocols so that a device  100  can operate in multiple systems without changing the transceiver. For example, in one embodiment, transceiver  106  is capable of implementing a combination of air interface  222  protocols such as GSM, TDMA, CDMA, and WCDM. Such a transceiver, therefore, is capable of operating in multiple variations of system  200 .  
         [0023]    In order for device  100  to work within a wireless communication system  200 , device  100  must be assigned a mobile number just like a mobile device  202 . In fact, a mobile device  202  can operate as a device  100 , i.e., a mobile device  202  may include a positioner  104  and a transceiver  106 . In this case, the mobile device  202  would have two mobile numbers; one for use in communicating voice and/or data and one for use in determining the location of the device. Therefore, there will be a plurality of mobile devices  202  and a plurality of devices  100  operating within system  200 . In one embodiment, a new field in the HLR would keep track of which mobile numbers where assigned to devices  100  for location services.  
         [0024]    If a device  100  is lost or stolen, then the owner of the device can activate transceiver  106  by placing a call to the mobile number associated with device  100 . When the owner places the call, transceiver  106  is activated and receives the call, which contains a request for position information related to the device. The request may be in the form of information encoded in the call, or it may be implied, i.e., the fact that the call is being received indicates that position information is being requested. Once transceiver  106  receives the position request, it begins obtaining position information from positioner  104 . The transceiver then transmits the position information, which is received by BSS  204  and routed to MSC  212 .  
         [0025]    The operator of system  200  may charge the user of a device  100  a flat rate for providing location services. Alternatively, or in addition to a flat rate, the operator may charge for the “airtime” used when locating device  100 . Thus, the location service associated with devices  100  can generate significant revenue for operators of system  200 . The impact on system capacity would be minimal, however, because devices  100  would only use air-time if they are lost or stolen.  
         [0026]    Once the position information reaches MSC  212  it is routed to a Local Control Center (LCC)  220  that is configured to determine the location of device  100  from the position information. In FIG. 2, LLC  220  is shown directly coupled to MSC  212 . In another embodiment, MSC  212  may be coupled to LCC  220  through public network  218 . In still another embodiment, however, LCC  220  may be integrated into a Network Operating Center (NOC) associated with system  200 . LCC  220  may even be integrated into NSS  210 .  
         [0027]    Alternatively, LCC  220  may not be incorporated into a wireless communication system such as system  200  at all. Instead LCC  220  may be part of a system dedicated solely to locating devices  100 . Such a system may, for example, operate as a paging system. In this case, LCC  220  may be directly coupled to BTSs  206  as shown in FIG. 3. In this embodiment, LCC  220  is interfaced to a local telephone company through network interface  307 . Network interface  302  can be a single line or several telephone line connections. For example, network interface  302  can comprise direct inward dial circuits, T 1  circuits, or network connections.  
         [0028]    As in the previous embodiments, a device  100  is assigned a number within system  300 . When a device  100  is lost or stolen, the owner can activate a transceiver  106  within the device by placing a call to the number. The call is connected to LCC  220  through network interface  302 . LCC  220  translates the call into paging information that is sent to BTSs  206 . In turn, BTSs  206  broadcast the information to devices  100 . The appropriate transceiver  106  will then respond to the page by transmitting position information back to LCC  220 . As such, LCC  220  may be incorporated into a control point (not shown) of an existing paging network, or a customized paging network such as network  300  can be utilized.  
         [0029]    Once the position information reaches the LCC, a map is constructed of the surrounding area and the particular device  100  is located within the map. Once the location and map have been acquired, this information can be communicated to a security service, the police, or some other third party, who can then recover the device. Optionally, the information can simply be forwarded to the device owner.  
         [0030]    For example, when a laptop owner losses the laptop or has it stolen, he can immediately call the mobile number associated with the laptop. The call is then routed to the correct wireless communication system  200 , which will verify through the HLR or VLR that the mobile number is used for location services. System  200  then communicates a position request to the laptop, which is received in a transceiver  106  within the laptop. The transceiver responds to the request with its current coordinates obtained from a positioner  104  within the laptop. The process is continuous throughout the call. In other words, as long as the call is active, transceiver  106  continues to obtain position information from positioner  104  and transmits it to system  200 .  
         [0031]    In the event that positioner  106  is unable to provide position information, transceiver  104  can, depending on the embodiment, transmit a continuous tone. For example, in a wireless communication system  200 , transmitting a continuous tone allows location via triangulation using BTSs  206 . For triangulation to be effective, the transmission from transceiver  106  must have some indication of the transmission timing; which will allow system  200  to determine how long it took the transmission to reach a particular BTS  206 . Essentially, transceiver  106  will broadcast the continuous tone to all BTSs  206  within range. When the tone is received at a BTS  206 , the timing information will allow a determination of how long it took the transmission to reach the BTS and therefore the distance between the device  100  and the BTS  206  can be determined. This distance will define the radius of a circle with the BTS at the center and on the perimeter of which the device  100  will be located. The intersection of three such circles, provides the location of the device.  
         [0032]    Inclusion of the location components, i.e., positioner  104  and transceiver  106 , within a device  100  should have a minimal impact on device  100 . In fact, the only real requirement is that the location components will need to draw a minimal amount of power while they are on standby and a slightly higher amount of power while they are operating. This, is illustrated in FIG. 4, where device power  402  is shown coupled to positioner  104  and transceiver  106 . Device power  402  may not always be available, however. For example, if device power  402  is an AC or battery supply in a laptop computer, the location components will not be able to draw power if the device is unplugged, or if the battery charge is depleted. Therefore, in certain embodiments, an independent power source  404 , such as a small battery is provided.  
         [0033]    In one embodiment including source  404 , device power  402  is coupled to the location components in parallel with power source  404 . In this case device power  402  is the primary source when it is installed, and power source  404  takes over only when device power  402  is removed. In one particular embodiment of this kind, power source  404  contains switching circuitry and device power  402  is actually coupled to power source  404 . Switching between the two supplies then takes place via the switching circuitry. In an alternative embodiment only power source  404  is coupled to the location components and the components do not draw any power from device power  402 .  
         [0034]    In order to minimize the impact of including the location components, in terms of cost and area, each component can be reduced to a single integrated circuit (IC), i.e., a positioner IC and a transceiver IC. Alternatively, the two components can be combined in a single location IC. In one embodiment, the single location IC also includes power source  404 . Therefore, in laptops and other devices in which space is a valuable commodity, and which do not already include a communications transceiver, the invention can be reduced to a single IC for inclusion in the device. In devices that do include a communications transceiver, such as a PDA or cell phone, only the positioner IC need be included. The communications transceiver included in the device can then be used to interrogate the positioner IC in response to the position request.  
         [0035]    It should be noted, that a location IC or individual transceiver and positioner IC can be optionally installed by including them on a removable media such as a SIM or PCMCIA card. Thus, for example, a PDA or cell phone may include a slot for installing a SIM card. To enable location determination, a SIM card that includes a location IC is installed in the slot.  
         [0036]    Moreover, use of the invention is not limited to portable electronic devices. For example, a location IC can be installed within a car radio. Such a location IC would need to include its own power source  404 , because once the car radio was removed from the car there would no longer be any device power  402 . Similarly, a location IC can be installed in home electronics. In fact, if a power source  404  is included, a location IC or combination of a transceiver IC and a positioner IC can be included or installed in any product that can be lost or stolen, such as, for example, a car, a bicycle or a motorcycle.  
         [0037]    Additionally, transceiver  106  is not limited to being a wireless transceiver. For example, transceiver  106  can be used to transmit and receive information over a computer network such as the Internet. In one embodiment of this type, transceiver  106  is activated when the device is connected to the network. Typically, LCC  220  is also directly connected to the network. Therefore, the position requests are generated and the position information is received directly by the LCC.  
         [0038]    While embodiments and implementations of the invention have been shown and described, it should be apparent that many more embodiments and implementations are within the scope of the invention. Accordingly, the invention is not to be restricted, except in light of the claims and their equivalents.