« 上一頁繼續 »
ON-DEMAND DATA SYSTEM
CROSS REFERENCE TO RELATED
 This application claims the benefit of U.S. provisional application Ser. No. 60/241,396 filed Oct. 18, 2000 entitled "On-Demand Data System," by Majid Chelehmal, Douglas Jones, Mukta Kar, William Kostka and Rouzbeth Yassini-Fard.
BACKGROUND OF THE INVENTION  a. Field of Invention
 The present invention pertains generally to digital networks and more specifically to a combined system using IP transports and MPEG-2 transports.
 b. Description of the Background
 On-demand systems that are capable of delivering video, audio, and other data on-demand over a cable system have been the desire of many cable operators for quite sometime. The technical difficulties of providing such a system have been substantial. For example, providing sufficient bandwidth to supply such services has presented many difficult problems. Latency and quality of service are associated problems. Further, the ability to provide access to large databases that can be made available from content providers has also posed many significant problems. For these reasons, it would be desirable to provide a video-ondemand system, or more generally, a data-on-demand system that allows a user to access large databases that can be made available from content providers and to display or otherwise make available selected video or other data according to a user's schedule. Further it would be desirable to provide a system that allows a user to access any large database in an on-demand fashion.
SUMMARY OF THE INVENTION
 The present invention overcomes the disadvantages and limitations of the prior art by providing an on-demand system that is capable of allowing a user to access large databases of one or more content providers to use such data according to a schedule selected by the user. Such data can comprise video data, audio data, textual data, or any other type of desired data.
 The present invention may therefore comprise a method of using a managed network and a video cable system to deliver video data on-demand from a content provider to a cable system user comprising; providing a listing of video data that is available from the content provider for selection by the cable system user, using a first transport mechanism that is compatible with said managed network to transmit the video data through the managed network to a cable system provider in response to a request by the cable system user, converting said first transport mechanism to a second transport mechanism that is compatible with the video cable system, transmitting the video data to the user through the video cable system using the second transport mechanism.
 The present invention may further comprise a method of translating a data stream suitable for transmission on an IP transport mechanism to a data stream suitable for
transmission on an MPEG transport mechanism comprising; separating timing data contained in the IP transport mechanism from content data, converting the timing data to adaptation information, placing the adaptation information in adaptation fields of the MPEG transport mechanism, combining said adaptation fields with corresponding content data.
 The present invention may further comprise a system for delivering video data on-demand from a content provider to a cable system user coupled to a cable system comprising; a content server that provides a listing of video data available from the content provider, a managed network coupled to the content server that is capable of transmitting the video data using a first transport mechanism upon receiving a request from said cable system user to produce a plurality of first transport data streams, a translator that translates the first transport data streams to a plurality of second transport data streams on a second transport mechanism that is compatible with the cable system.
 The advantages of the present invention are that a user can access one or more large databases of information such as video data that the user can select and display, listen or otherwise use in accordance with the user's schedule. For example, the user may be able to select a particular movie and have that movie displayed immediately or at any desired start time. Further, the user may wish to listen to certain selections of music or other audio information which can be selected and listened to according to the user's schedule. Even further, the user may wish to access certain video games or other type of information that may be stored digitally by a content provider and that can be made available by selection according to the user's choice and schedule. In fact, any type of desired data can be accessed in an on-demand fashion for use by the user according to the user's schedule including any type of application programs.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a schematic illustration of a user's system that is employed in accordance with the present invention.
 FIG. 2 is a schematic block diagram of the overall system of the present invention.
 FIG. 3 is a schematic illustration of the data stream of the IP transport that is transmitted through the manage IP network.
 FIG. 4 is a schematic illustration of the MPEG transport of the compressed video data stream.
 FIG. 5 is a schematic illustration of the MPEG transport of the program table data.
 FIG. 6 is a schematic flow diagram of the functions performed by the translator.
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENT OF THE INVENTION
 FIG. 1 is a schematic block diagram illustrating the portion of the system that is employed by the user of the present invention. As shown in FIG. 1, a cable 10 is deployed or otherwise made available in a location, such as the user's home, where the present invention may be used. Cable 10 can comprise any standard cable drop that is connected to an existing cable network such as the cable
networks that are currently in widespread use. Cable 10 is capable of providing high bandwidth digital and analog signals. Cable 10 is connected to set top box 12 that is a microprocessor based system capable of performing various functions as disclosed below. Set top box 12 receives MPEG-2 transport data streams via the Cable 10. Content data such as movies and program information is supplied via the MPEG-2 transport data streams on cable 10 to set top box 12 as compressed MPEG-2 data. Set top box 12 is connected to TV/monitor 14 for display of video and textual data and presentation of audio data. The set top box decodes information provided on the cable and converts the data to analog data for display and presentation on an analog TV/monitor 14. The set top box that is utilized in accordance with the present invention, therefore, can constitute the standard set top box that is currently in use for digital cable systems. Billing systems used in conjunction with the set top box can also be used in a similar fashion with the present invention.
 FIG. 2 is schematic block diagram of the system embodying the present invention. As shown in FIG. 2, antenna 20 receives digitally modulated rf signals. These signals may be transmitted by satellite, microwave link, or other means. A series of integrated receiver transcoders (IRTs) 22,24,26 demodulate the signals, decode the signals, and identify individual data packets according to ID numbers on the packets so that they can be separated into individual channels. For example, each IRT 22, 24, 26 has an associated data stream with corresponding packet IDs that it recognizes and decodes. Each of the data streams is then up-converted to a different frequency channel by upconverters 28, 30, 32. Each of the up-converted signals is then applied to directional couplers 34, 36, 38 for coupling onto the cable 40. The cable 40 is then distributed to numerous subscribers such as subscribers 43, 44. Numerous amplifiers exist throughout the cable system 40, such as amplifiers 46, 48. Each of the subscribers that subscribes to digital TV has a set top box such as set top box 50 of subscriber 42. Using an input device 52, the subscriber can operate the set top box 50 to select any one of a number of channels that are provided on the cable 40. The set top box also functions as a digital to analog converter to convert the digital contents of the signals to an analog signal for display on the analog TV/monitor 54. If TV 54 is a digital TV/monitor, the set top box can transmit the digital signal for display on the digital TV. Input device 52 can comprise a standard remote control device that uses ir signals to control the TV/monitor 54.
 As also shown in FIG. 2, each of the set top boxes, such as set top box 50, is provided with a key that is capable of decoding various channels that are provided on the cable 40. For example, a subscriber may only subscribe to a basic channel subscription package that does not include any premium channels. In that case, a subscriber 42 would have a set top box 50 that is supplied with a decoding key that is only capable of decoding the channels that are provided on cable 40 that correspond to the basic cable subscription. Likewise, a subscriber that subscribes to the highest grade of cable package is provided with a key that is capable of decoding all of the channels except for the pay-per-view channels.
 As FIG. 2 also illustrates, a number of channels are dedicated to pay-per-view in accordance with standard digi
tal cable TV programming. If a subscriber would like to view a pay-per-view channel, the subscriber would normally call the head end 21 and place an order for pay-per-view. The subscriber identifies himself by the address or telephone number that is cross-linked by the head end to an ID number for a particular set top box for that particular subscriber. The head end then transmits a key to the set top box of the subscriber so that the subscriber can view the particular pay-per-view broadcast. Alternatively, the subscriber can simply select a pay-per-view program from a program listing. The set top box then sends the request back to the head end. The head end transmits a key, in the same fashion, to the set top box that has placed the order. The pay-per-view is then set for a showing at a particular time and is broadcast to all subscribers. The subscribers having the key to decode the pay-per-view broadcast can then view that particular pay-per-view broadcast on the designated channel at the time it is broadcast. The requests for on-demand data operate in a similar fashion and can use the standard billing processes that are currently in place for the pay-per-view system.
 Referring again to FIG. 2, head end device 21 may also program the cable 40 with analog broadcast signals. As shown in FIG. 2, this may typically occur by the head end device utilizing an antenna 54 that receives standard broadcast signals over the airways. For example, these may be standard broadcast signals from ABC, NBC, CBS, UPN, Fox, PBS, etc. Each of these analog signals may then be up-converted and assigned a separate channel as shown by up-converters 56, 58. Head end 21 then places these analog signals on the cable 40 using directional couplers 60 and 61.
 Currently, most cable companies offer both digital and analog service. In that regard, content received by the IRTs 22,24,26 may also be converted to analog signals and placed on the cable 40. Similarly, the content received by antenna 54 may also be included in the downlink transmission that is received by antenna 20 so that antenna 54 and the associated up-converters 56, 58 can be eliminated.
 The video-on-demand, or in general, the data-ondemand system of the present invention, in comparison to pay-per-view, or similar systems, allows a user to access large databases having a great deal of content at the convenience of the user. The user can select content from content providers for delivery to the user at a time that is desirable for the user which does not correspond to a pre-planned broadcast time. Content servers 60, 62, 64 can comprise any number of different servers that have access to very large databases with a large amount of content. For example, Turner Broadcasting may own the rights to display thousands of movies that are stored in a database and accessible through a content server that is operated by Turner Broadcasting. Each of these content servers 60, 62, 64 is connected to a managed IP network 66. The managed IP network 66 provides a guaranteed quality of service by managing various layers of protocol of the network 66. In essence, the managed IP network 66 provides a virtual dedicated line in the network to guarantee delivery of data packets in a fashion that provides the required quality of service. The managed IP network 66 uses real time protocol (RTP), user datagram protocol (UDP) and internet protocol (IP) to ensure that data packets are transmitted from the content servers 60, 62 and 64 to translator 68 so they can be decoded as an uninterrupted stream.