Abstract:
An information distribution and processing system contains a remote site, a sender and a receiving apparatus. The remote site contains a first set of digital data. The sender delivers a second set of digital data to the receiving device. In one embodiment of the present invention, the receiving device contain a timing device for automatically receiving the second set of digital data at predetermined times. The second set of digital data contains a first set of displayable data, a second set of displayable data, at least one non-displayable symbol, and at least one linking reference associated with the second set of displayable data. If desired, a user can select the second set of displayable data. The associated linking reference is sent to the remote site. The associated linking reference is used by the remote site to search for the additional information, and returns the requested information to the user.

Description:
This application is a continuation of U.S. patent application Ser. No. 10/073,124, filed Feb. 9, 2002 now abandoned; which is a continuation of application Ser. No. 09/812,003, filed Mar. 19, 2001 (now U.S. Pat. No. 6,349,409); which is a continuation of application Ser. No. 09/434,413, filed Nov. 4, 1999 (now U.S. Pat. No. 6,317,785); which is a continuation of application Ser. No. 08/939,368, filed Sep. 29, 1997 (now U.S. Pat. No. 6,021,307); which is a continuation in part of application Ser. No. 08/644,838, filed May 10, 1996 (now abandoned); which is a continuation in part of application Ser. No. 08/279,424, filed Jul. 25, 1994 (now abandoned); and application Ser. No. 08/255,649, filed Jun. 8, 1994 (now abandoned); which is a continuation in part of application Ser. No. 08/224,280, filed Apr. 7, 1994 (now abandoned); all of which are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to information distribution and processing, and more particularly to distributing information using a broadcast channel and a bi-directional communication channel. 
   2. Description of the Prior Art 
   Recent advances in modem and computer technology allow large amount of digital data to be transmitted electronically. A number of information providers (such as newspaper and magazine publishers) and on-line information distributors (such as America Online, Dialog and Nexis) have formed partnerships to deliver newspaper and other information on-line. In this system, a subscriber uses a computer and a modem to connect (e.g., through a regular phone line) to the computer of an on-line information distributor. The subscriber can retrieve information, including newspaper articles, stored in the computer of the information distributor. 
   On-line delivery of newspaper has many advantages. For example, the information can be updated throughout the day while the printed version is printed only once or twice a day. Further, it is possible to do text-based searches on the information. However, it is found that on-line deliver of newspaper and other information is slow. For example, a subscriber has to wait many seconds for a newspaper article to be delivered. The quality of the electronic newspaper is low. For example, in order to reduce storage and communication requirements, graphic images appeared in the printed version are not universally supplied in the on-line version of newspaper. One of the reasons for such poor performance is the limited bandwidth of communication channels used by on-line information distributors. Another reason is that information is centrally processed by the computer at the site of the information distributor, with the result that each subscriber only gets a small slice of the time of the computer. 
   Another way to communication information on-line is through the Internet, which is a worldwide interconnection of millions of computers, from low end personal computers to high-end mainframes. An important development in the Internet is the World Wide Web (the “Web”). The Web is a wide-area hypermedia information delivery and retrieval system aimed to give universal access to a large universe of documents. When the Web was first developed around 1989, it was known to and used by the academic/research community only as a means for fast disseminating of information. There was no easily available tool which allows a technically untrained person to access the Web. An important development is the release of a Web “browser” around 1993. It has a simple but powerful graphic interface. The browser allows a user to retrieve web documents and navigate the Web using simple commands and popular tools such as point-and-click. Because the user does not have to be technically trained and the browser is easy to use, it has the potential of opening up the Internet to the masses. 
   A document designed to be accessed and read over the web is called a web page. Each web page must have an address in a recognized format—the URL, or Uniform Resource Locator—that enables computers all over the world to access it. Each web page has an unique URL. A web page typically contains both text and images. It is also possible to include audio and movie data. 
   The Web faces the same problem as the regular on-line delivery of information. This is because most people use the above described modem to access the Internet. Thus, the data transfer rate of the Web is also limited. Because multimedia data (comprising a combination of text, graphic, video and/or audio) has a large data size, even when compressed, it could take a long time to retrieve a document from the Web. Further, it is difficult to prevent unauthorized persons from access a web-page because more than 20 million people in the world has access to the Internet. 
   Consequently, there is a need to have an improved system for distributing information electronically. 
   SUMMARY OF THE INVENTION 
   The present invention uses two channels to deliver digital information: a broadcast channel and a bi-directional channel. The broadcast channel is used to deliver the bulb of the digital information to subscribers. The amount of information delivered is preferably sufficient to satisfy the needs of a large number of subscribers so that they do not have to obtain additional information using the bi-directional channel. The broadcast information is stored on fast storage media located at subscriber sites. As a result, search and retrieval of the broadcast information is quick. Further, the broadcast information is processed locally using a dedicated on-site processor instead of relying on the computers of the information distributors. As a result, the load on the computers of the information distributors is reduced. If the subscribers desire to receive additional information relating to the broadcast information, the bi-directional communication channel is used to transmit the request and the requested information. 
   The distribution costs of broadcast channels are typically much lower than that of a bi-directional communication channel. Consequently, the major portion of information is delivered using low cost distribution channels. For a large number of subscribers, the broadcast information will provide all the information they normally need. Thus, expensive bi-directional communication channels are used only occasionally. 
   These and other features and advantages of the present invention will be fully understood by referring to the following detailed description in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic drawing showing an embodiment of an information distribution system of the present invention. 
       FIG. 2A  shows a newspaper article as displayed on a monitor of the information distribution system shown in  FIG. 1 . 
       FIG. 2B  shows the contents of the broadcast information which corresponds to the newspaper article of  FIG. 2A . 
       FIG. 3  shows another embodiment of the information distribution system of the present invention. 
       FIG. 4  shows an embodiment of the present invention used in a data communication network. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention comprises a novel information distribution and processing system and related methods. The following description is presented to enable any person skilled in the art to make and use the invention. Descriptions of specific applications are provided only as examples. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
   The present invention can be used to solve the above described problem of digital information delivery. It uses two channels to deliver digital information: a broadcast channel and a bi-directional channel. The broadcast channel is used to deliver the bulb of the digital information from a source to subscribers. The time for broadcasting is preferably during a time of low communication load (e.g., off-peak hours). Upon receiving, the broadcast information is stored on storage media located at subscriber sites. If the subscribers desire to receive additional information relating to the broadcast information, the bi-directional communication channel is used to transmit the request and the requested information. 
   The data transfer rate of the storage media (more than a million bytes per second) could be hundreds of times faster than that of a modem. As a result, search and retrieval of the broadcast information is quick. Further, the broadcast information is processed locally using a dedicated on-site processor instead of relying on the computers of the information distributors. As a result, the load on the computers of the information distributors is reduced. Even though the requested information is delivered using a regular low bandwidth communication channel, the performance of the system would not be severely affected because the requested information is only a small fraction of the broadcast information. 
   In one embodiment of the present invention, the broadcast information can be sent in the clear while the requested information (which may contain commercially valuable information) is encrypted. Because the amount of requested information is a small fraction of the broadcast information, there is no need to use much computer resource to process the requested (and encrypted) information. In a different embodiment of the invention, the broadcast information is encrypted using a simple algorithm while the requested information is encrypted using a complex algorithm. Even though extra computer resource is used to decrypt the broadcast information, this embodiment may be useful for the case where it is not desirable for the public to view the broadcast information. 
   It should be noted that the word “channel” is not limited to a specific kind of physical communication link. The word “channel” merely means a path for communicating information. The term “broadcast channel” means a path allowing an information source to deliver digital information to many recipients almost simultaneously. The term “bi-directional channel” means a path allowing one-to-one interactive communication between a source and a recipient. These two “channels” could use the same physical communication link (e.g., telephone lines, television cable lines, wireless, optical links, etc.) to perform their respective functions. That is, the same physical communication link can support both broadcast and bi-directional channels. 
     FIG. 1  is a block diagram of an information distribution system  250  in accordance with the present invention. In this embodiment, system  250  is designed to electronically distribute digital newspaper. It should be pointed out that system  250  can also be used advantageously to distribute other types of digital information. System  250  contains a plurality of subscriber units (such as units  252  and  254 ) each connected to a bi-directional communication channel (e.g., modems  256  and  258  coupled to units  252  and  254 , respectively) and a satellite transponder  260  for broadcasting digital data to these subscriber units. Modems  256  and  258  may be coupled to a database  259  via line-based or wireless telephone communications. In system  250 , satellite transponder  260  is used to broadcast the content of a newspaper to the subscriber units while telephone modems  256  and  258  allow delivering additional information (stored in database  259 ) to subscriber units  252  and  254 , respectively, on a demand basis. 
   The structure of these subscriber units are substantially identical; consequently, only one of these units, such as unit  252 , is described in detail. Unit  252  contains an antenna  266  for receiving broadcast signals from satellite transponder  260 , a signal/data processor  268  for performing signal and data processing functions, a monitor  270  for displaying the digital newspaper, and an input device  272  (such as a keyboard and/or a mouse). 
   Signal/data processor  268  contains a transponder interface  282  for processing transponder signal received from antenna  266 . Transponder interface  282  preferably contains a low noise receiver for receiving high frequency (e.g., C or Ku band) transponder signal and a universal data interface for converting the transponder signal to digital data. The retrieved data is stored in nonvolatile storage  284 , such as a hard disk or solid state flash memory. Preferably, satellite transponder  260  broadcasts the newspaper data at predetermined times. Thus, a real-time clock  286  is preferably used to turn on interface  282  at the predetermined times. Processor  268  contains a microcomputer  290  which coordinates the operation of clock  286 , nonvolatile storage  284 , and interface  282 . Microcomputer  290  preferably contains a central processing unit (CPU), random access memory (RAM) and peripheral interface devices. Processor  268  also contains a communication interface  292  for sending and receiving digital data from database  259  through modem  256 . 
   The time for broadcast is preferably chosen when communication load of transponder  260  is at a low level (e.g., around mid-night). As a result, the cost of information delivery is low. Alternatively, the time of broadcasting is chosen by transponder  260  because it knows when communication load is light. In this case, transponder  260  first sends a signal to signal/data processor  268  for alerting processor  268  to receive and process the newspaper information. 
   A user can use the input device  272  and monitor  270  to read the content of the digital newspaper stored in nonvolatile storage  284 . In one embodiment, the complete content of the newspaper is stored in nonvolatile storage  284 . The term “complete content” means that the user is able to read the newspaper without relying on information stored in database  259  (although other embodiments may deliver less than the complete content). In this aspect, system  250  functions in a similar way as the distribution of a conventional printed newspaper. However, the digital data of the digital newspaper delivered by satellite transponder  260  preferably contains linkage references (such as pointers) which allow fast retrieval of additional information from database  259 . 
   If the newspaper information received from satellite transponder  260  is sufficient to satisfy the needs of a user, signal/data processor  268  will not activate modem  256 . However, if the user wishes to receive additional information relating to an item mentioned in the digital newspaper (e.g., by selecting the item using the input device), processor  268  will retrieve the information stored in database  259  using the embedded linkage reference. 
   In system  250  of the present invention, the received digital newspaper (including graphics and other multimedia contents) is stored in nonvolatile storage  284 , which has fast access time. Further, a dedicated processor (i.e., microcomputer  290 ) is used to process newspaper information. On the other hand, prior art on-line newspaper distribution systems rely on modem to deliver the content of the newspaper stored in a central site. Further, the processor in the central site has to serve many users in delivering the newspaper. As a result, system  250  has superior performance compared to prior art on-line newspaper delivery systems. 
   In one embodiment of the present invention, commercially valuable information is encrypted and stored in database  259 . The broadcast information does not contain this information. Thus, in this embodiment less than the complete content is delivered by the broadcast channel. In this case, the broadcast information would not be useful unless a decryption key is available to decrypt the information obtained from database  259 . As a result, only subscribers who have a decryption key are able to obtain meaningful information from the newspaper. In the case, microcomputer  290  also performs decryption functions. Alternatively, a separate decryptor  294  can be included in signal/data processor  268 . 
   It should be appreciated that even though only one database is shown in  FIG. 1 , the valuable information could be distributed to several databases. Further, the digital newspaper and database  259  could be physically located in the same site. 
   If it is not desirable for the public to read the broadcast information, the data transmitted by transponder  260  could also be encrypted. In this case, simple encryption algorithm could be used to encrypt the broadcast information while complex encryption algorithm is used to encrypt the valuable information in database  259 . A potential hacker would not be motivated to decrypt (and make public) the broadcast information unless he/she can also decrypt the valuable information. 
     FIG. 2A  shows an example of a portion of a newspaper article as seen on monitor  270 . In  FIG. 2A , the terms which a user may obtain additional information are underlined (or highlighted in other ways, such as setting in different colors, depending on the choice of the publisher). If desired, the user may select these terms using an input device (e.g., a pointing device, such as a mouse), and signal/data processor  268  will obtain the additional information from database  259 . 
     FIG. 2B  shows the same portion in  FIG. 2A  as transmitted by transponder  260  (for simplicity, other embedded formatting codes, such as center, bold, etc., are not shown). Each of the terms underlined in  FIG. 2A  are enclosed by a special symbol (e.g., the “           ” symbol) and followed by a linkage reference enclosed by another special symbol (e.g., the “         ” symbol). These symbols are invisible to the users and is recognizable only by microcomputer  290 . The linkage information could be as simple as a pointer.
   When an underlined term in  FIG. 2A  is selected by a user, microcomputer  290  extracts the linkage reference and transmits it to database  259 . The linkage reference allows database  259  to retrieve the necessary information quickly without doing extensive searches. As a result, the response time of system  250  is fast. The retrieved information can itself contains linkage references and can be searched. 
   If the speed of searching and retrieving data by database  259  is fast, it may not be necessary to include linkage reference in the broadcast information transmitted by transponder  260 . In this case, the user-selects (e.g., using an input device such as a mouse) words and terms he/she is interested in. Signal/data processor  268  transmits the selected items to database  259 , which searches for matches in its database. Matched information is sent to subscriber unit  252  for processing. 
   The bi-directional channel also allows updating of the broadcast information. There is typically a time difference between the broadcast and display of information. New information gathered during this time difference can be stored in database  259  and later transmitted to signal/data processor 
   In this embodiment of the present invention, satellite transponder  260  is used as the vehicle to electronically broadcast newspaper. However, other broadcast distribution methods can be used. One method is to use the Internet to broadcast the information. Also note that the broadcast distribution channels do not have to be electrical. For example, the present invention allows the distribution of CDROMs encoded with digital information to the subscriber sites. In the case of electrical broadcast communication channels, both wired and wireless can be used. Preferably, unidirectional channels are used for broadcast because of their low cost; however, the present invention does not preclude the use of bi-directional communication channels (such as telephone lines) as means for distributing broadcast (i.e., one to many) information. 
   Current technology allows the size of antenna  266  to be as small as 2 feet. The costs of antenna  266  and transponder interface  282  is already low enough to be within the reach of small business or a typical household. The newspaper publisher has to pay for the use of the transponder. However, the costs is comparable to the printing and distribution costs of printed newspaper. It is anticipated that the costs of the newspaper distribution system in accordance with the present invention will be lowered as the number of subscribers increases. 
     FIG. 3  shows another embodiment of a newspaper distribution system  200  of the present invention. System  200  contains a satellite transponder  210 , an earth station  214 , and a plurality of subscriber units, such as units  222  and  224 . Transponder  210  functions in a similar way as transponder  260  of  FIG. 1  and subscriber units  222  and  224  function in a similar way as subscriber units  252  and  254  of  FIG. 1 . Earth station  214  receives digital data transmitted by transponder  210  using an antenna  216 . The data is distributed to subscriber units  222  and  224  via wired communication channel  228 , such as cable and optic fiber. Other earth stations could be placed in strategic locations throughout the country to serve their respective subscribers in a similar manner as earth station  214  and subscriber units  222  and  224 . As a result, a large geographic area can be served simultaneously by satellite transponder  210 . The advantage of this embodiment is that the equipment costs incurred by the subscriber units are low. 
   In some locations, it may not be desirable to use wired communication channel to link an earth station to subscribers. In such case, wireless communication channel could be used.  FIG. 3  shows an earth station  234  which receives transponder signal from transponder  210  using an antenna  236 . Earth station  234  in turn broadcasts the digital data to its subscribers, such as subscriber units  242  and  244 . 
     FIG. 3  shows a plurality of modems that are connected to subscriber units  222 ,  224 ,  242  and  244 . These modems are connected to a database  246 . These parts of  FIG. 3  is similar to the corresponding part of  FIG. 1 . It should be noted that wired communication channel  228  may also be used as a bi-directional communication channel for accessing database  246 . 
   In one embodiment of system  200 , teletext technology is used to link earth station  234  and subscriber units  242  and  244 . Thus, earth station  234  could be located adjacent to a television transmission station. The digital data received by earth station  234  can be integrated to the vertical blanking interval of a TV signal, which is broadcasted using an antenna  238 . Subscriber units  242  and  244  receive the signal using antennas  239 , and  240 , respectively. The digital data is then retrieved. Various improvements and refinements of the teletext technology are well known and can be incorporated into system 
   It should be obvious to a person skilled in the art that systems  250  and  200  are not limited to the distribution of newspaper. Further, digital newspapers of the future may contains contents which are not available in the printed version, such as multimedia compositions. Other information, such as magazines, graphic images, electronic mails, computer games, multimedia work, or interactive movie, could also be advantageously distribution using a system similar to systems  250  and  200 . For example, if it is desirable to distribute interactive movie, the non-interactive portion can be broadcast while the interactive portion is delivered using a bi-directional channel. 
   The present invention can also be used in information distribution using a digital data network.  FIG. 4  is a drawing showing a network system  500  of the present invention. System  500  contains a data communication network  502 , which could be a local area network or a wide area network. System  500  also contains a plurality of client computers (such as computers  506 - 508 ) and a plurality of server computers (such as servers  516  and  518 ). These computers are connected to network  502  using a plurality of network access devices  510 - 514  (such as modems for connecting the client computers to dial-up lines and channel service units for connecting the server computers to T1 lines or lines of higher data rates). Preferably, the digital newspaper data and the database is stored in the servers. The digital newspaper data will be broadcasted by a server to the client computers either at a predetermined time or upon request. Upon receiving the broadcast data, the clients stores the data in its nonvolatile memory (such as its hard disk). 
   The structure of the client computers could be similar to subscriber unit  252  of  FIG. 1 , except that the antenna (such as antenna  266 ) may correspond to the connection from the client computers to network  502  and interface  282  may correspond to the network access device. For example, client computer  510  may contain a signal/data processor  521 , a monitor  522 , an input device  523  and an antenna  524 . The client computers can communicate with the database server (which corresponds to database  259  of  FIG. 1 ). It should be noted that both the database and the digital newspaper data could be located on the same server. Further, the digital newspaper data and the database information could be distributed among many servers. 
   In  FIG. 1 , the bi-directional channel is a separate physical communication link (i.e., telephone  256 , which is different from a satellite link). In  FIG. 4 , it is possible to use network  502  as both the broadcast channel and the bi-directional channel. This is an example that the same physical link supports both broadcast and bi-directional channels. Thus, these channels are defined by their functionality instead of by their physical characteristics. 
   In the Internet, information can be broadcasted by sending the same information to a plurality of electronic mail or URL addresses. Alternatively, information can be sent using a multicasting protocol. The client computers contain a browser which could read the broadcast digital information. The database server contains a plurality of files containing information related to the broadcast information. In the Web environment, the broadcast information is a hypertext markup language (“HTML”) document contains links (e.g., in the form of HTML “tags” containing URL addresses of these related files in the database server). A user can use a browser running on a client computer to read the broadcast HTML document. These tags are typically rendered as highlighted text or images by the browser. Upon seeing these indication of links, a user can click on these indications, and the client computers can accesses information in selected files by sending requests to these URL addresses. The server can then deliver the requested information to the subscribers using standard Web protocol. As pointed out above, these files may be encrypted, and only authorized users can read the content of these files. 
   Some networks systems support distributive processing. These networks allows “applets” to be distributed from one computer (client and sever) to another computer for execution. An example of such a system is the Java and HotJava environment on the Web. The present invention can be applied to these network systems. Only some of the applets (preferably the most important ones) need to be encrypted while most of the applets can be sent in the clear (or slightly encrypted). 
   In the embodiments shown in  FIGS. 1 ,  3  and  4 , the encryption can be performed at the time information in the database is delivered to the subscribers. Different encryption keys could be used. Methods of delivering the decryption keys to the subscribers via insecure communication channels have been described above, and will not be repeated here. 
   There has thus shown and described a novel information distribution and process system. Many changes, modifications, variations and other uses and application of the subject invention will become apparent to those skilled in the art after considering this specification and the accompanying drawings. All such changes, modifications, variations, uses, and applications are covered by the scope of this invention which is limited only by the appended claims.