Abstract:
The present invention provides a method for finding the location of a mobile device user, and using the location to customize the information and to determine the way of delivering such information to the user. The mobile device user may request the information either with an interactive series of one or more requests, or by pre-selecting the type of message to be delivered. The customized information is transmitted only to the mobile device from which the request is originated. It can also be displayed at a public display unit (such as an electronic billboard), sent to a public broadcaster, posted on the Internet, or sent to a fax machine or a modem. The present invention also provides a method for determining traffic density and speed information that can be continuously updated. The traffic information together with a variety of traffic services can be transmitted to mobile devices users, displayed at inanimate devices (such as electronic billboards), publicly boradcasted, or posted on the Internet.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to wireless communications systems. More particularly, it relates to providing location-based information to mobile communication devices. 
     BACKGROUND ART 
     As wireless communications rapidly spread into every walk of modern life and approach a state of ubiquity, the demand for the bandwidth (or content) of information transmission in wireless communications networks is also growing. A great deal of effort has been devoted to providing location-specific information to mobile device users in a timely, accurate, interactive, and customized manner, that in turn reduces the bandwidth need and required user interaction. 
     U.S. Pat. No. 5,636,245, for example, describes a method for determining whether access to particular information transmitted by a broadcaster is appropriate for a particular remote unit (such as a mobile device). The method is particularly useful for distributing situation awareness information. U.S. Pat. No. 5,493,709 discloses a radio receiver using current frequency and coordinate data transmitted by a mobile device as a basis for selecting traffic message pertinent to the user of the device, such that traffic data are automatically selected without requiring traveler&#39;s input. U.S. Pat. No. 5,548,586 discloses a mobile packet communication system and method which are capable of transmitting packet data only to a selected base station in whose service cell a mobile device requesting the data is operating, without transmitting the data to all base stations in the same area. U.S. Pat. No. 5,684,859 discloses a system for providing paging information to roaming subscribers in a convenient and efficient manner to make the change of geographic area as seamless as possible. U.S. Pat. No. 5,898,680 describes a system and method for distributing data (particularly map data and other types of image data) to users by means of a radio frequency link, so that up-to-date data can be obtained as frequently as needed. (In this case, although remote users can obtain data selectively, there is no two-way communication between the users and the source of the data.) U.S. Pat. No. 5,900,825 describes a system and method for providing information to an operator of a vehicle. It requires, however, the vehicle to be equipped with a position determining means (using GPS or signals received from a local transmitter site, for example) and compares the position of the vehicle to the location indicated by each message. When a match is found, the receiver system provides the matching message to the operator. U.S. Pat. No. 5,627,549 describes a system and method for sending specific time and location sensitive advertising information to a moving vehicle. There have also been other efforts on transmitting messages targeted to a specific geographical group of mobile device users, as exemplified by U.S. Pat. Nos. 5,565,909 and 5,432,542. 
     With prior art systems, the users of mobile communication devices are not allowed to communicate with their respective information service networks in an interactive and personalized manner to tailor information received in the context of their location for example. That is, the information is generic and broadcast to a group of users in the same geographical region, rather than being tailored and targeted to a particular user. Moreover, some of the prior art systems require a third party device, such as a GPS unit, to facilitate generating and delivering the location information. 
     What is needed in the art, therefore, are innovative ways of delivering accurate location-specific information to mobile device users in an interactive, user-tailored and multimedia fashion without requiring the user&#39;s mobile device to have inherent location capability. 
     SUMMARY 
     The present invention provides a method for using the RF signal characteristics, or information derived therefrom, of the receiving wireless device to customize the delivery and or content of information to the receiving wireless device, for one or more wireless devices, including, but not limited to, mobile wireless communication devices. In addition, information can be customized by criteria selected by the wireless device user, the information content provider, or the information broadcaster. Customization of information can include generating, modifying, and/or deleting the information content, and regulating the delivery of information content to the mobile device so as to optimize the usage of capacity and decrease the burden on the user. 
     Information that can be transmitted to wireless devices may reside in a remote database. Information can be content for delivery to wireless devices and criteria to regulate that delivery. Information content can be generic, location and/or velocity centric, and location and/or velocity modified generic data. Examples of generic content are: product promotions, facility usage directions, neighborhood yard sales and events, road and civil construction, and area map information. 
     Examples of location and/or velocity based content are: mobile device current location, average traffic speed on current or alternate roadway sections, traffic alerts of congested or slow-speed areas, and current directional bearing of travel. An example of location and/or velocity-modified generic content is: dating service based on proximity of wireless device users. 
     In addition, delivery criteria may be associated with the information content, and can be used to regulate the transmission of the information content. Delivery criteria can be related to the content-provider, the user, and/or the broadcast service provider. 
     Delivery criteria provided by the information content provider can include, but is not limited to time and duration criteria. Examples of time criteria may include store operation hours associated with particular information content, and time periods associated with scheduled road maintenance. Examples of duration criteria may include the amount of time after content posting to transmit content associated with promotional details in the content, or the amount of time after transmission of the content that the content is valid for, and/or other time-sensitive matters related to the content. 
     User related delivery criteria may be related to location and personal preferences of the user. Location-related criteria may include, but is not limited to location information, and/or mobile device movement information such as distance, speed, and/or bearing. Examples of location information criteria may include the location of stores selling a product contained in the information content, the location of a traffic accident, or the road containing a traffic accident. Examples of mobile device distance information may include the maximum distance between a mobile device and a store contained in the information content, or the maximum distance between a mobile device and a public danger, such as a traffic incident that may be blocking an exit. An example of mobile device speed information may include a speed range that traffic is moving on a road or highway and information content suitable for highway travelers who may be benefited by the knowledge of that information. An example of mobile device direction information may include information content that can be sent when a receiver is less than a first maximum distance away and conditionally sent if the receiver is less than a second, greater maximum distance and the receiver direction is towards the location associated with the information content. 
     A mobile device user can provide user-related criteria to information providers or information broadcasters by requesting location-specific information either with an interactive series of one or more requests, or by pre-selecting the type of message to be delivered. Pre-selected conditions for a message may include, time, location, radial distance, commercial services, advertising information, pricing information, traffic conditions or events, and public safety and emergency announcements, to name but a few. 
     Location of a mobile device is determined using at least one location determining base station site. Information meeting the pre-selected conditions is then transmitted to the mobile device from which a request originated or which was preselected by the user, without imposing any special requirement on the user&#39;s device, or involving a third party (e.g., GPS, or a plurality of base stations). Location-specific information that is time sensitive also can be delivered in real-time or close to real-time. Moreover, location-specific information alternatively can be displayed at a public display unit (such as an electronic billboard), posted on the Internet, or sent to a fax machine, printer, variable message sign, local range radio or a modem. By application of this capability, the present invention also enables an information service network to generate and deliver location-specific information tailored to a plurality of mobile device users. 
     In accordance with one embodiment of the present invention, an antenna array at a base station receiver of an information service network receives direct path and multipath signals transmitted from a mobile device. The base station determines one or more signal signatures from a subspace of array covariance matrices derived from the received signals. The signature then is compared to a database of calibrated signal signatures and corresponding locations, and a location , which has a calibrated signature best matches the measured signature is selected as the most likely location of the mobile device. In accordance with one embodiment of the present invention, the database of calibrated signal signatures and corresponding locations is generated by a calibration procedure in which a calibration mobile device transmits location data derived from a GPS system to the base station which records the location information together with the signal signature of the calibration device. A more detailed description of this method is given in U.S. Pat. No. No. 6,026,304 issued on Feb. 15, 2000 to Hilsenrath et. al., the entirety of which is incorporated by reference for all purposes. 
     Knowing the location of the mobile device in an accurate and timely fashion allows the information service network to determine the information that the mobile device user is interested in, and consequently delivers the pertinent information in a timely fashion. The information service network may provide further information to the user in an interactive and user-tailored fashion, or update the information on a regular or a pre-scheduled basis. 
     In accordance with another aspect of the above location finding method is that it needs only a single base station, in contrast to multiple base stations employed in the prior art methods. Moreover, it does not impose any specific requirement on the mobile device, therefore allowing the wireless network to support all types of mobile devices currently deployed. 
     Further, the method does not impose a requirement on the mobile device to be communicating with the location network at the time of location determination. 
     Using a location-finding method of the present invention, traffic density and speed information readily can be generated and continuously updated. Accordingly, real-time traffic information and services, commercial services, and public safety and emergency announcements can be transmitted to mobile device users, displayed at passive display devices (such as electronic billboards) placed in one or more designated areas, or a combination of both. Such information also can be broadcast publicly, posted privately on the Internet, or sent to fax machines or modems. 
     Furthermore, merchants and information kiosk users can benefit from the ability to send and/or receive location-specific information of interest, such as targeted advertisements and special services, to travelers and shoppers. 
    
    
     The novel features of this invention, as well as the invention itself, will be best understood from the following drawings and detailed description. 
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 depicts one embodiment of a method of the present invention for generating and delivering location-specific information to a mobile communication device; 
     FIG. 2 shows another embodiment of the present invention for generating and delivering location-specific information to an inanimate device; 
     FIG. 3 depicts yet another embodiment of the present invention for generating and delivering location-specific information tailored to a plurality of mobile communication device users. 
     FIG. 4 shows an exemplary embodiment of the present invention for determining traffic density and speed on a roadway. 
    
    
     DETAILED DESCRIPTION 
     Although the following detailed description contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following preferred embodiment of the invention is set forth without any loss of generality to, and without imposing limitations upon, the claimed invention. 
     The present invention employs systems and methods for accurately determining the location of mobile devices using a single base station. More specifically, signals transmitted by a mobile device are detected by an antenna array at a base station that is part of an information service network (e.g., a cellular telephone network Based upon the signals received, the base station determines a signal signature, which can be a subspace of an array covariance matrix constructed from a set of p-dimensional array vectors derived from the received signals. In general, the signal signature is any location-dependent feature derived from the set of direct and multipath signals received at the antenna array of the base station transmitted from a given location. The signature may be derived from any combination of amplitude, phase, delay, direction, and polarization information of the signals. 
     Preferably, the signature is substantially invariant with respect to all variables unrelated to the location of interest, such as noise. A more detailed description of this method is given in U.S. Pat. No. 6,026,304, issued on Feb. 15, 2000 to Hilsenrath et. al., the entirety of which is incorporated by reference for all purposes. 
     After the signal signature has been determined, it is then compared to a database of calibrated signal signatures and corresponding locations. The database of calibrated signal signatures and corresponding locations can be generated by a calibration procedure in which GPS location data of a calibration mobile unit is associated with the signal signature of the calibration mobile unit received at the base station. By searching such a database, a location which has a calibrated signature associated with it that best matches the measured signature is selected as the most likely location of the mobile device. The entire location finding process takes place within seconds, fractions of seconds or near real-time. 
     A feature that distinguishes this method of location finding from the prior methods is that it can accurately determine a location from a single base station, in contrast to multiple base stations employed in the prior art. A further aspect of this method of location finding is that it can determine the position of any mobile device, not limited to those subscribing to a given information service network or currently communicating with the location network. 
     FIG. 1 depicts one embodiment of the present invention for generating and delivering location-specific information to a mobile device user. A single site base station  10 , equipped to receive signals with an antenna array, receives a request for information from a mobile device  11 . The request is then forwarded to a message generator  12 . Both the base station  10  and the message generator  12  are connected to a location generator  13 , which, in turn, is connected to a location database  14 . The location generator  13  determines location information from the received signals by using, for example, the location finding method describe above, and sends the location information so obtained back to the message generator  12 . The message generator  12  then compiles the location information with other information pertinent to the specific location of interest, which comes from an information database  15 . (The information database is assumed to be a part of the information service network hereinafter, although it can also be an external information service provider with which the network is in communication.) A time manager  16  also may provide an input to the message generator, if time sensitive issues are involved. The compiled message comprising requested location-specific information is then sent from the message generator  12  to the base station  10 , and subsequently transmitted to the mobile device  11  by the base station  10 . 
     Upon receiving the location-specific information, the mobile device user may send one or more follow-up requests to express certain preferences (for a gas station, a restaurant, or a shopping center, for instance), or require additional information. The information service network will respond accordingly. There can be a sequence of back-and-forth communications between the mobile device user and the network. 
     The information requested by the mobile device user also can be transmitted to a public display unit, such as an electronic billboard, as depicted in FIG.  2 . In accordance with this exemplary embodiment, a motorist  20  on a roadway sends a request for information (for example, the location of the nearest gas station) to a base station  21  of an information service network  23 . The base station is also in communication with an electronic billboard  22  placed along the traveling path of the motorist. The base station  21  transmits the requested information, or information deemed appropriate by the network, to the electronic billboard  22 , to be viewed by the motorist. (The base station may or may not notify the motorist about the location of the message being displayed.) 
     Moreover, a mobile device user can request information to be delivered in a pre-selected and pre-scheduled manner. For example, a user may request a message to be displayed on a billboard placed on a specific roadway on a specific day, so that a target user will be greeted with the message when driving past the sign on that day. A traveling sales person may want information about local weather, food and lodging services to be delivered to him/her through a mobile device (or a public display unit placed at an airport, or train station) upon arriving in each city on his/her journey. Such information also can be made available on the Internet, or sent to the person&#39;s fax machine or modem. 
     FIG. 3 shows another embodiment of the present invention. A plurality of mobile device users, including motorists  30  and  31  and a pedestrian  32 , send information requests to a base station  33  of an information service network  35 . The nature and content of information requested may vary from one user to another. For example, the motorist  30  may request for the location of the nearest gas station; the motorist  31  may inquire about the location of the nearest shopping mall; whereas the pedestrian  32  may want to know the location of the nearest restaurant. These information requests are processed at the network, and the replies to these requests are subsequently directed to the respective mobile users by the base station  33 . One or more replies can also be displayed at a designated public display unit  34 . The replies to information requests may be in the form of text messages, interactive voice responses, a voice from a live operator, or any other means of replying to such requests and displaying responses. 
     The present invention also provides a method for determining traffic density and speed on roadways, as illustrated in FIG. 4. A base station  40  of an information service network  41  receives signals from a plurality of mobile device users, such as users  42 ,  43 ,  44 , and  45 , traveling in a roadway segment. By determining the locations of these users, the information service network can provide an estimate of the density of travelers in the segment of interest. Moreover, by continuously sampling the signals transmitted by the users on the roadway at certain time intervals, the network can derive an estimate of the speed of traffic in the segment of interest. The traffic density and speed information thus obtained is stored in a traffic database at the network. The information service network can send such traffic information to mobile device users on the roadway upon request, or display the traffic information at one or more public display units, such as units  46  and  47  along the roadway that can be continuously updated. In addition, the traffic information can be forwarded to a central database where information can be compiled, archived and otherwise stored for later retrieval. 
     The information service network can compile an extended traffic database by sampling traffic densities and speeds in different segments of a roadway and on various roadways in a specific geographical area. Using this information, the information service network can offer a variety of traffic services to mobile device users traveling in the area accordingly. For instance, it can alert the users of traffic congestion or other hazardous conditions occurring in a particular roadway segment upon request or on a pre-scheduled basis, and suggest alternative routes to those who may have intended to travel to the problematic segment. It also can diligently monitor the users who are approaching the problematic segment and automatically send out traffic avoidance messages. Moreover, the traffic database generated at the network can be shared with traffic controllers, public broadcasters (e.g., television and radio broadcasters), or posted on the Internet, so to inform the public at large. Traffic engineers can use the traffic database to study the correlation between one congested segment and others, so to provide more effective travel planning services. In addition, public safety and emergency announcements, commercial advertising information, and many other services can also be made available to mobile device users. In all cases, the present invention enables the delivery of these services to be timely, effective, comprehensive and seamless. 
     The method of the present invention for generating and delivering traffic information, commercials, information and corresponding services is not limited to roadway traffic. It also can be applied to pedestrian traffic, air traffic, marine traffic, ski traffic, delivery fleets, commercial vehicle operators and many other types of traffic. Moreover, the method of the present invention can be used to monitor demographic pattern and behavior. 
     An instance of such a pattern might be the observation of traffic flow whether vehicular or pedestrian. Such information may be used to determine the routes most commonly taken. This information can act as the basis of planning studies, marketing plans and positions of public messages. It also can be used by the operators of cellular and other wireless networks to deploy capacity sites or reposition existing assets to maximize the usage of those assets. Such planning is typically performed by labor intensive and expensive processes, which may now be easily automated. 
     Expand to fleet management. It is another purpose of the invention to deliver route information to a mobile device after the mobile device user has provided at least a destination location. While additional information can be provided by the user, this is not required for essential route information delivery. The system would determine the current location of the mobile device user. Static information about route paths in the area would then be consulted. The route delivery service would then determine the most optimal route based on length of paths available; RF signal characteristics and information derived therefrom, from transmitting mobile wireless devices in the area, that includes but is not limited to: traffic density and speed on sections of paths; and optionally on user-selected criteria. After delivery of optimal route information, the service could then re-determine the optimal route at intervals, or as conditions change, during the user&#39;s progress. 
     It is also apparent to those skilled in the art that the exemplary embodiments described above may be altered in many ways without departing from the principle and the scope of the invention; and numerous embodiments can be further derived from the present invention. Accordingly, the scope of the invention should be determined by the following claims and their legal equivalents.