Enhanced mobile communication device, and transportation application thereof

Abstract

An enhanced mobile communication device communicates directly with other enhanced mobile communication devices in an ad-hoc mode over a wireless medium. The device transmits and receives packets of digital data. The packets of digital data are such that when transmitted, the probability that they will be received by the other mobile communication devices is increased. The probability is further increased by transmitting the packets a multiple and variable number of times according activity in the wireless medium. Attempts to transmit are made periodically and the period of transmission is adjusted according to activity in the wireless medium. In a transportation application, the packets comprise vehicle traffic congestion update information. The device maintains a traffic database and a map database. Traffic congestion update information is exchanged with other devices. Routes through the map from a source or current position of the device to a destination are computed according to an analysis of the traffic database.

What is claimed is:  
     
         1 . A mobile communication device for communicating directly with other mobile communication devices in an ad-hoc mode over a wireless medium, the mobile communication device comprising: 
 application means for constructing a packet of digital data;    connection means responsive to said application means for connecting to the wireless medium;    transmitting means responsive to said connection means for transmitting the packet of digital data over the wireless medium; and    receiving means in communication with said connection means for sensing the wireless medium and receiving a receive packet of digital data from the other communication devices;    wherein said application means constructs the packet with a limited and variable length such that when transmitted by said transmitting means the probability that the other mobile communication devices receive the packet of digital data is increased.    
     
     
         2 . The invention of  claim 1  wherein said connection means comprises: 
 defer means for delaying the transmission of the packet; and  
 back-off means responsive to said defer means for performing a back-off operation for avoiding contention for the wireless medium.  
 
     
     
         3 . The invention of  claim 1  wherein said application means further comprises multiple transmit means for increasing the probability that the other mobile communication devices receive the packet of digital data by causing said connection means and transmitting means to transmit the packet of digital data a multiple and variable number of times.  
     
     
         4 . The invention of  claim 3  wherein the multiple and variable number of times is one, and wherein said application means comprises packet length limit means for limiting the length of the packet from around 800 bits to around 1200 bits.  
     
     
         5 . The invention of  claim 3  wherein the multiple and variable number of times is n, and wherein said application means comprises packet length limit means for limiting the length of the packet from around 800+n*400 bits to around 1200+n*400 bits.  
     
     
         6 . The invention of  claim 3  wherein the sensing of said receiving means comprises sensing link quality, wherein the multiple and variable number of times varies according to the link quality, and wherein the limited and variable length of the packet varies according to the link quality.  
     
     
         7 . The invention of  claim 1  wherein said connection means, said transmitting means, and said receiving means operate according to an 802.11 standard.  
     
     
         8 . The invention of  claim 1  wherein said application means further comprises timer transmitting frequency means for causing the mobile communication device to transmit the packet of digital data every one second.  
     
     
         9 . The invention of  claim 1  wherein said application means further comprises timer transmitting frequency means for causing the mobile communication device to transmit the packet of digital data periodically and to vary the period of transmission.  
     
     
         10 . The invention of  claim 9  wherein the period of transmission is varied according to a simple-increase-multiple-decrease method.  
     
     
         11 . The invention of  claim 1  wherein the receive packet comprises traffic congestion update data, and wherein the mobile communication device further comprises: 
 a map database; and  
 a traffic database for storing the traffic congestion update data;  
 wherein said map databases and said traffic database is accessible by said application means; and  
 wherein said application means further comprises a vehicle navigation application for determining a first route from a source to a destination of the mobile communication device through segments of said map database.  
 
     
     
         12 . The invention of  claim 11  wherein the first route is determined according to a shortest path algorithm.  
     
     
         13 . The invention of  claim 11  wherein said vehicle navigation application further comprises a traffic flow estimation application for estimating traffic patterns by analyzing the traffic congestion update data in said traffic database, and for determining an alternate route from the source to the destination of the mobile communication device through segments of said map database.  
     
     
         14 . The invention of  claim 13  wherein said traffic flow estimation application further comprises means for evaluating if the end-to-end delay of the alternate route is at least one minute greater than the end-to-end delay of the first route, and if the end-to-end delay of the alternate route is at least ten percent shorter than the first route.  
     
     
         15 . The invention of  claim 11  wherein said vehicle navigation application further comprises a safety warning application.  
     
     
         16 . The invention of  claim 11  or  13  wherein the mobile communication device further comprises a user interface for indicating routes to a user of the mobile communication device.  
     
     
         17 . The invention of  claim 16  wherein said user interface comprises a visual indicator.  
     
     
         18 . The invention of  claim 16  wherein said user interface comprises an audible indicator.  
     
     
         19 . The invention of  claim 11  further comprising a data port for accessing said map databases and said traffic database.  
     
     
         20 . The invention of  claim 11  further comprising an IEEE 802.15 port in communication with said application means.  
     
     
         21 . The invention of  claim 11  further comprising a removable storage device in communication with said application means.  
     
     
         22 . The invention of  claim 11  wherein the mobile communication device further comprises a vehicle mobility means in communication with said application means for monitoring position and speed of the mobile communication device.  
     
     
         23 . The invention of  claim 22  wherein the packet of digital data constructed by said application means comprises the position and speed of the mobile communication device.  
     
     
         24 . The invention of  claim 23  wherein the packet of digital data further comprises at least some of the traffic congestion update data in said traffic database.  
     
     
         25 . The invention of  claim 22  wherein the packet of digital data constructed by said application means comprises a beacon service table.  
     
     
         26 . The invention of  claim 22  wherein the packet of digital data constructed by said application means comprises a vehicle service table.  
     
     
         27 . The invention of  claim 1  wherein the mobile communication device further comprises a vehicle mobility means in communication with said application means for monitoring position and speed of the mobile communication device.  
     
     
         28 . The invention of  claim 27  wherein said vehicle mobility means comprises a global positioning system receiver.  
     
     
         29 . In a transportation network comprising a plurality of routes and a plurality of vehicles each traversing the transportation network from a current position to a destination, wherein at least some of the vehicles comprise a local traffic database, a vehicle navigation method, the method comprising: 
 (a) communicating the traffic databases directly between at least some of the vehicles in the transportation network;    (b) for at least some of the vehicles and local to each vehicle, analyzing the traffic database local to each vehicle; and    (c) for at least some of the vehicles and local to each vehicle, computing a route from the current position to the destination according to the analysis in (b).    
     
     
         30 . The invention of  claim 29  further comprising for at least some of the vehicles and local to each vehicle, providing at each vehicle driving directions such as to enable at least some of the vehicles to traverse the computed route in (c).  
     
     
         31 . The invention of  claim 29  further comprising repeating steps (a), (b), and (c).  
     
     
         32 . A transportation application method for a first vehicle traversing a path from a current position to a first destination in a transportation network comprising a plurality of vehicles, the method comprising: 
 (a) periodically receiving at the first vehicle traffic congestion update information from at least one other vehicle of the plurality of vehicles in the transportation network;    (b) periodically determining local to the first vehicle the current position of the first vehicle;    (c) periodically analyzing local to the first vehicle the traffic congestion update information, a traffic database, and a map database;    (d) determining a route from the current position of the first vehicle to the first destination through the transportation network based on the analysis in (c); and    (e) storing the traffic congestion update information in the traffic database.    
     
     
         33 . The invention of  claim 32  wherein the traffic congestion update information is received directly from the at least one other vehicle of the plurality of vehicles.  
     
     
         34 . The invention of  claim 32  further comprising periodically transmitting local to the first vehicle at least some of the traffic database directly to the at least one other vehicle.  
     
     
         35 . The invention of  claim 32  further comprising periodically transmitting local to the first vehicle transmit traffic congestion information comprising the position determined in (b) directly to the at least one other vehicle.  
     
     
         36 . The invention of  claim 34  or  35  further comprising varying the period of transmission.  
     
     
         37 . The invention of  claim 32 ,  33 ,  34 , or  35  wherein the transmitting and receiving steps further comprise transmitting and receiving according to an 802.11 standard.  
     
     
         38 . The invention of  claim 32  wherein if the first destination is replaced with a second destination while in transit to the first destination, determining a route to the second destination in accordance with steps (a) through (c).  
     
     
         39 . The invention of  claim 32  further comprising computing an alternate route to the first destination in accordance with steps (a) through (c).  
     
     
         40 . An enhanced transportation network method in a transportation network comprising a plurality of vehicles, the method comprising: 
 (a) periodically receiving traffic congestion update information from at least one other vehicle of the plurality of vehicles in the transportation network;    (b) periodically analyzing the traffic congestion information, a traffic database and a map database;    (c) determining a route from a source to a destination through the transportation network based on the analysis in (b); and    (d) storing the traffic congestion update information in the traffic database.    
     
     
         41 . A transportation network comprising: 
 a plurality of mobile communication devices, each mobile communication device traveling with a vehicle traversing the transportation network, wherein each mobile communication device comprises a local traffic database and a local map database; and    an ad-hoc wireless communication network;    wherein said plurality of mobile communication devices transmit and receive traffic congestion update information over said ad-hoc wireless communication network; and    wherein the traffic congestion update information is stored in the local traffic database of each mobile communication device according to an analysis of the traffic congestion update information.    
     
     
         42 . The invention of  claim 41  further wherein the local traffic database, the local map database, and the traffic congestion update information is analyzed local to each of said plurality of mobile communication devices.  
     
     
         43 . The invention of  claim 41  wherein the communication network is an 802.11 ad-hoc network.  
     
     
         44 . The invention of  claim 41  wherein the communication network is Wi-Fi communication network.  
     
     
         45 . The invention of  claim 41  wherein the traffic congestion update information comprises a beacon service table.  
     
     
         46 . The invention of  claim 41  wherein the traffic congestion update information comprises a vehicle service table.