HK1086694A - Cable television system and method for compatible bandwidth upgrade using embedded digital channels - Google Patents

Description

Cable television system and method for upgrading compatible bandwidth using embedded digital channels

RELATED APPLICATIONS

This is a partial continuation of USSN10/319,617 (inventors Ciciora, Hartson and Dickinson) entitled "Expanded Information capacity for Exclusive Communication Transmission Systems" filed on 9/8/2002, which is a division of USPN 6,433,835 entitled "Expanded Information capacity for Exclusive Communication Transmission Systems" filed on 17/4/1998 and authorized on 13/8/2002, which is also International application No. PCT/99/08513 filed on 16/4/1999, entitled "Expanded Information capacity for Exclusive Communication Transmission Systems" filed on 16/4, 1999, which is incorporated by reference herein in its entirety. This document is also a partial continuation of USSN10/246084 (Long, Endres, Ciciora and Hartson) entitled Adaptive Expanded Information Capacity for communications systems, filed 2002, 9, 18.9.2002, which is hereby incorporated by reference. Priority is also claimed for USSN 60/325,003 entitled "High speed data Compatible In Cable Analog Television Signals" filed on 25.9.2002 and USSN 60/353,478 entitled "Cable Television Compatible BandwidthUpdate Using A Virtual Channel System" filed on 31.1.2002, which are both hereby incorporated by reference.

Technical Field

The present invention relates to cable television delivery systems for providing television programming and other broadband content to a user's home. More particularly, the present invention relates to systems and methods for increasing the capacity of such systems to carry additional standard television programs, personalized on-demand programs, and other information by embedding digital signals as an underlay to channels on the analog layer (analog tier) of the system in a manner that allows simultaneously transmitted analog programs to be undisturbed. The digital signal is then decoded at and near the user's home and remodulated onto the remaining bandwidth available on the existing cable television system for eventual distribution to the user's existing cable modem or set-top box and television receiver.

Background

Cable television (also sometimes referred to as community antenna television or CATV) was developed in the late twentieth and forty years and served rural communities where television signals could not be received due to terrain or distance to television stations. Cable television system operators place antennas in areas with good reception, pick up commercial broadcast station signals, then distribute them to subscribers over coaxial cables and charge a fee. In the fifties of the twentieth century, only 70 communities in the united states operated cable television systems. These systems serve approximately 14,000 homes. By 2001, there were cable television systems in approximately 32,000 residential areas, serving approximately 8 million subscribers. Cable systems are operating in many states in the united states and in many other countries (including austria, canada, belgium, germany, uk, italy, japan, mexico, spain, sweden and switzerland).

The number of program channels that a cable television system is capable of carrying depends on the type of headend equipment utilized and the electrical properties of the system cabling, amplifiers, taps, and other components. Channel capacity in the industry has increased significantly in recent years; several systems now offer over 100 channels. Most cable television systems in the united states are technically capable of providing 36 to 60 channels, meaning that they operate between 330 and 450 MHz.

The large channel capacity in a cable television system makes it possible for a system operator to provide a large number of services. In addition to television broadcast signals available over-the-air (off-air), most systems now also offer a variety of programming services available only to cable subscribers, including special entertainment programming, news, sports, weather, business information, and many movies. They also provide so-called "position-in-place" (niche) programs, which are designed for specific audiences such as children, women, and various ethnic and racial groups. Some cable operators also set up their own local programming and provide access channels for public and social public agency use. They also provide a leased access channel for "leasing" to those viewers who wish to display a particular program. Electronic banking, shopping, utility meter reading, and home security are some home services that may use the two-way transmission capabilities of some cable television systems.

At the same time, users also want faster and richer content and better quality of the content they receive. With the growth of personal computers in the nineties of the twentieth century, easy-to-use graphical interfaces now facilitate users in selecting and viewing MPEG and other streaming content, listening to MP3 music files, conducting telephone conversations over the internet (sometimes with video assistance), and processing and storing digital images in JPEG or other formats. Because the richness of this content greatly exceeds the capacity of typical dial-up telephone modems, users have moved to so-called "broadband" connections. However, the telephone infrastructure does not support this "digital subscriber line" service in all areas, and many cable operators have begun to provide full range of communication services, including high speed internet access and local telephone services. High speed internet access allows subscribers to connect to the internet using a cable modem at 100 times faster than a modem based on a standard analog telephone.

The demand for an expanded body of programming and rich media, coupled with competitive pressure from companies distributing a wide selection of movies and programming via satellite, has caused cable operators to face strong pressure to increase the bandwidth of their existing systems. But doing so requires investing in expensive new head end equipment and laying new more expensive cables to each street block. The new cable must then be equipped with new distribution amplifiers and other electronics that must even be spaced differently from the lower bandwidth system.

What is needed by cable operators is a technique that enables them to increase the number of channels of programming and other forms of broadband services that they can deliver without having to make a complete infrastructure rebuild. To address this unresolved need, embodiments of the present invention add the additional digitized programming needed as an embedded inner layer of the existing analog programming. This is achieved by exploiting the fact that analog television signals are based on systems designed over half a century ago that do not use the maximum information capacity of the standard 6MHz television spectrum occupied by each channel (both in air-borne and cable systems), and therefore have the opportunity to incorporate more information without reducing its ability to transmit television programs intended for transmission and without changing the physical cable infrastructure required to transmit it.

The new program is then extracted in or near the home using relatively inexpensive equipment and remodulated onto a frequency above the highest frequency used by the cable operator on the system. This new "private channel" or signal is then sent over the home's existing cable line to a cable modem or decoded by the home's existing set-top receiver and displayed on the television. This is possible because the distance that higher frequency signals need to travel in the home is relatively short, and most cable modems and set-top receivers are standardized to operate in almost all cable systems and are capable of handling frequencies well above or below 450MHz carried by more typical cable systems.

Summary of The Invention

Various embodiments of the present invention provide apparatus, methods and systems for implementing bandwidth augmentation in a manner that is compatible with most common cable television systems. The present invention will achieve this by embedding one or more data carriers within one or more analog television channels at the system head end. The preferred embodiment will use the dNTSC or dPAL scheme described in the relevant documents referenced, where the data is injected and modulated substantially in quadrature to the visual or video carrier, making it theoretically "invisible" to a typical user-level television receiver.

The system then uses means for decoding one or more channels in which the data has been embedded. The apparatus can be located in a cable subscriber's home or in a neighboring node serving multiple homes. In both cases, the extracted data is re-modulated onto one or more local "private channels" (typically 64 or 256QAM) and then up-converted to unused frequencies, typically in unused channels or just above the last used cable channel. For example, if a cable system transmits 78 television channels (at 52 to 550MHz, whether analog or digital) on channels 2 to 79, various embodiments of the present invention will recover the embedded data signal and remodulate the signal (with or without additional embedded signals) to channel 80 at 556MHz or higher.

Although there is an upper limit to the frequencies that may be transmitted by both the coaxial cable lines and the cable set-top boxes in a home, various embodiments of the present invention are able to operate within these limits because coaxial cables or other wiring systems designed to operate to 550MHz (by way of example only) can successfully operate at higher frequencies for relatively short distances in a home. Moreover, from an economic standpoint, digital cable set-top boxes and cable modems are typically designed to operate to at least 860MHz, regardless of the bandwidth of the system in which they are employed, wherein the system simply does not utilize the full capacity of the set-top terminal if less than 860 MHz.

The "private channel" is remodulated to a digital carrier compatible with a commercial digital cable television set-top box such as those available from Scientific Atlanta or motorola. The "private channel" content would then be decoded and output to a standard television receiving device in a manner consistent with the cable industry standard digital carrier, thus eliminating the need for a special decoder for viewing virtual channel content.

Techniques are known in the art for modulating signals to establish local "private channels" (sometimes referred to as "virtual" or "pseudo" channels) at frequencies that are not used within the cable operator's frequency band, or at frequencies above the highest frequencies used by the cable operator. A different application is taught as an element of several patents authored by one of the inventors of the present invention (Hoarty), and another variation is in the public domain and used by some consumer video installers to distribute DVD, audio and confidential camera video content from one central location to other locations in the home.

In addition, one or more "private channels" can be remodulated in a manner compatible with the cable standard DOCSIS (cable data service interface specification) for demodulation by commercially available broadband cable modems.

The purpose of the conversion to a standard cable digital carrier (64 or 256QAM) is to eliminate the need for a consumer digital set-top box or consumer cable modem in the user's home. This is achieved by a virtual channel changer device that can be placed at a node of the cable system in the center of the served neighborhood, or in the cable terminal of the customer premises, or even behind the television set or in front of the cable set-top box. This scheme also allows multiple cable set-top boxes or cable modems in a house to access these new, locally established "private channels" and the programming or other content they carry.

In another embodiment, the "private channels" can be extracted from the analog carrier in which they are embedded and decoded in a private proprietary set-top box or a private proprietary cable modem. However, this solution is generally not popular with cable operators. The above scheme of decoding and conversion to a standard digital modulation format provides a significant upgrade to existing cable television operations.

In addition to the additional encoding devices that must be installed at the cable system headend, the only material loss to the cable operator is the additional decoding device that would need to be added to the local neighborhood node, or in various alternative embodiments, the "door roll" is also needed to enable the technician to install one decoder box in the user's home. However, it is possible in various embodiments of the invention to have a user install the decoding device in the home by simply connecting the decoder/converter in series with an existing cable set-top box, but the use of the entire house would be limited.

It is also possible to build the required decoder means into existing commercial cable set-top boxes and commercial cable modems, but the migration of such new equipment into existing cable equipment is slow due to several logistical (local) problems.

This conversion process can be made economical by the fact that in various embodiments, the digital data embedded by the proprietary process at the headend can be encoded with Forward Error Correction (FEC) that is already compatible with commercial digital set-top boxes. Such FEC schemes are typically reed-solomon error correction with proper interleaving of data blocks. The decode-and-convert apparatus need only detect and then demodulate the embedded data signal and then remodulate the data signal to a scheme compatible with the particular cable television system, which again will typically be 64 or 256 QAM. FEC processing will then not be needed in the detector converter device.

It is envisioned that various embodiments of the present invention will use dNTSC or dPAL (as described in more detail in the referenced related applications) as a means of inserting digital data into a television signal transmitted over a cable television system. It will be apparent to those skilled in the art, however, that any system or technique capable of embedding compatible digital signals into television signals at sufficient data rates will be used as part of the various embodiments of the system or method of the present invention.

It is an object of various embodiments of the present invention to enable a cable operator to significantly increase the effective bandwidth a particular cable system can deliver to a subscriber's television or computer without investing in making a complete re-establishment of physical cable equipment.

This and other objects and advantages of various embodiments of the present invention will become apparent to those skilled in the art after a review of the following description, the drawings and the appended claims.

Brief Description of Drawings

Fig. 1 is a high-level general schematic diagram of an overall system showing various embodiments of the present invention that may be used in a cable television system.

Fig. 2 is a more detailed schematic diagram of the head end element.

FIG. 2a is a more detailed schematic diagram of a "virtual personal video recorder" feature enabled by certain embodiments of the present invention.

Fig. 3 is a schematic diagram of an embodiment utilizing an embedded carrier-to-physical carrier processor with a multiplexer.

Fig. 4 is a schematic diagram of an embodiment utilizing direct conversion of an embedded carrier to a physical carrier.

Fig. 5 is a schematic diagram showing an embodiment using a digital set-top box.

Fig. 6 is a schematic diagram of the manner in which various embodiments of the present invention use the cable television system spectrum.

Detailed description of the invention

Various embodiments of the present invention provide apparatus, methods and systems for significantly increasing the effective bandwidth of a typical cable television system without requiring an entire system rebuild (including new cabling, amplifiers and other major asset upgrades to the cable plant infrastructure). Briefly, embodiments of the present invention provide an apparatus and method by which a cable television system operator can add additional programming by inserting digital data into a regular television program broadcast on an analog layer in such a way that the program does not appreciably interfere with the sound or appearance of the program when it is received at any subscriber's home and displayed on a typical consumer-grade television set.

The inserted digital data is then transmitted with the television program using existing cable system infrastructure and then extracted at or near the home of the cable subscriber. The data is then remodulated onto frequencies not used by the cable operator for transmission to the home, transmission at home and reception by existing industry standard set-top boxes or cable modems, and movies, music, web pages or other programs are played or displayed in industry standard ways.

Overview

A high level overview of a preferred embodiment of the present invention is shown in figure 1. The diagram shows a cable system headend, a cable system, a subscriber's home, and various points at which data may be extracted and remodulated according to various embodiments. Embodiments of the present invention are capable of delivering any type of digital content including full length feature films, video games, news and sports, and computer data files. In some embodiments, the content is available on-demand by the user, while in other embodiments, the content may be viewed in real-time as it is broadcast or streamed from the provider.

Various embodiments will also support Personal Video Recorder (PVR) type programming in which a user is able to view a television program in real time on a cable channel as it is broadcast, but with the option of pausing the program and resuming the program at some arbitrary later time, depending on the user's selection. This "pause and resume" function requires a separate "private" television channel to be provided to the cable subscriber when the viewer activates the pause function while all viewers are watching the same cable television channel when watching the same scheduled television program.

To provide such a mix of broadcast and viewer-controlled programming, a significant number of separate, television bandwidth channels need to be provided. For example, a medium cable television system serving 50,000 subscribers would require 5,000 private television channels if 10% of the cable television viewers wanted to take advantage of the on-demand features of the system (including, in this example, the PVR-type "pause and resume" feature). Virtually none of the existing cable television system architectures meet this requirement. It is an object of some embodiments of the present invention to meet the actual and technical requirements for providing such bandwidth-intensive enhanced services without requiring an economically impractical full reconstruction of the cable television equipment.

Fig. 1 illustrates two types of content entering a network at a head end. The first is an existing television program 101a, which is processed by an existing cable headend processor. In the case of local programming, the content typically arrives from a nearby television broadcast facility via a direct terrestrial link or an aerial antenna, and in the case of cable-only channels such as CNN, MTV, HBO, etc., the content arrives via satellite. The second type of content 102a is intended for interactive services and is typically reached through an internet connection, satellite, DVD, or other digital distribution media.

The interactive content 102a is provided on-demand by 102, wherein local data storage is maintained. The on-demand content is metered by 102 and encoded for transmission. The encoded on-demand content is embedded in a given NTSC (or PAL) television carrier using a proprietary process known as dNTSC. The embedding process occurs at this frequency or at an intermediate frequency known in the art as "IF". Some or all of the analog television channels of 101 are passed 102 and an embedding process is performed at 102. The broadcast channels and the interactive content embedded in the broadcast channels are combined in 103 and, if necessary, may be up-converted to their designated television channels. These combined channels are then modulated as a block onto the trunk line leaving the head-end. These trunk lines (105a, 105b and 105c) are typically fiber optic cables, but conventional coaxial cables are still sufficient to support the present invention. Moreover, by using multiple trunk lines away from the headend to carry cable television services to separate service neighborhoods, certain embodiments of the present invention can take advantage of this distribution and use spatial multiplexing by placing a unique set of interactive channels on each trunk line away from the headend, thereby effectively multiplying the private channel capacity of the system.

In this example, the optical trunk signal is converted to an electrical signal adjacent to the fiber optic bridge amplifier 105 b. Following the optical receiver is an embodiment of the present invention 106 that provides embedded channel extraction and processing for the corresponding neighborhood of subscribers. These embedded channels are decoded and remodulated or directly converted to the appropriate frequency to present the viewer or viewers requesting the service. The new channel is placed on a channel not used by the cable television system. The unused channel is typically higher than the last cable channel used by the non-interactive portion of the cable system. Because the moderate cable television system in the united states offers 60 channels and uses 450MHz of bandwidth, and most television tuner subsystems for cable-compatible television sets and VCRs can tune to 860MHz, a suitable residual bandwidth gap (up to 410MHz) is also reserved in which to place the newly generated interactive (private) channel.

The invention claims three methods of utilizing embedded information, which are: the embedded information is extracted by 106 at the adjacent cable node 105b and remodulated to new, unused frequencies and then these newly generated channels are distributed through the subscriber neighborhood served by the node. This process is repeated on a neighborhood-by-neighborhood basis to reuse the same blocks of newly generated frequencies in a space division multiplexing fashion as is known in the art. This is one of the most economical embodiments of the invention, but is also most limited to private channel generation. Another method places a device 112 similar to 106, called an "entire house decoder," on or within the subscriber premises to generate private television channels for distribution in the home and use by any television or computer (in the case of high speed cable modem service provided) in a manner similar to 106. The device 112 is typically located at a service entrance into a home, such as a garage or basement, or a service rack located on a property. This approach greatly increases the private channel carrying capacity of the present invention, but is more costly because it requires one "whole house decoder" for each subscriber who wants interactive services. An "entire house decoder" is capable of providing multiple channels outputting private entertainment or internet access within the capabilities of a home coax connection, but at frequencies above the highest available channel of the cable television system. As with the neighboring node embodiment 105, the entire house decoder 112 extracts private content for the house served from the main broadcast channel using dNTSC embedded data system. A third approach is to decode the embedded signal in a cable set-top box that serves only one television set and possibly has an ethernet jack on the backplane that provides high-speed internet access by using an embedded channel as a downstream pipe (assuming a DOCSIS compatible return path is included in the set-top box). This third embodiment is the least economical, but it provides the maximum capacity to serve the interactive subscribers.

To understand the concept of private channels, once generated at the headend and inserted into the channel group, the private channels are extracted 106 and then distributed at the newly generated frequency through the "fiber service area" served by the neighborhood node. For example, a viewer of television set 110 requests a Video On Demand (VOD) movie. The television set is assigned a private (virtual) channel generated at the head end by the video-on-demand server through an appropriate purchase and distribution mechanism. The private channel leaves the VOD server and is encoded by the present invention at 102. The encoded program is carried as an embedded signal within one or a portion of the broadcast television channels within the main set of non-interactive television channels on a particular trunk line serving the vicinity of the requesting viewer. For example, assume that a cable television system provides a medium number of 60 program channels. The private, embedded VOD channel is then extracted and remodulated by the inventive apparatus 106 and up-converted to channel 61 for tuning and descrambling by the set-top decoder 109 and viewing on the television 110. Only the requesting viewer's set-top box will descramble and display the program on a television attached to the set-top box, although the system can also support enabling multiple televisions to view the same private channel.

On demand program

In addition to typical cable television processing that occurs at the cable system headend, fig. 2 illustrates how certain preferred embodiments of the present invention add a means 201 for receiving and storing various types of interactive audio and video content, including video on demand content. The content can be received by any practical means including, among many others known in the art, satellite links, internet access, or tape. A session manager apparatus 202 responds to requests from system users via return path information 202a of the cable television plant. This information carries the unique identification of the user and the request from the user via the cable set-top box in the user's home.

The request may be to subscribe to a service (e.g., purchase a video-on-demand movie) and to control the currently viewed program. An example of a control program would be to fast forward or rewind a currently playing movie. Another example of control provided by the session manager would be to pause a live television broadcast and allow the viewer to resume from any point where the live program was paused. This is accomplished by storing digital television content received via satellite or other means or digitized in real time from a live analog broadcast in a video database storage device that stores for later retrieval any program content and allows playback from any point in the program. Figure 2a will illustrate this function in more detail.

All sources of content available as private programming channels to viewers are some form of digital video or audio or both. The session manager 202 instructs the inverse multiplexer 203 to route the private channel program from the on-demand database 203a or the virtual PVR subsystem 203b to the designated dNTSC encoder to propagate as one virtual channel to the requesting user's set-top box for decoding and viewing. Alternatively, the same private program can be routed to an existing transport multiplexer in the headend to be mixed with existing broadcast digital channels for further distribution to the requesting subscriber for decoding on that subscriber's cable set-top box decoder.

In the case where the dNTSC embedded carrier is used as a private channel path to the user, the user requested private channel leaves the inverse multiplexer 203 and is modulated by the dNTSC encoder 204 onto the data sub-carrier and added to the analog television signal in a manner that does not interfere with the image or sound of the main channel as described in the previously referenced patent 6,433,835. Once inserted into the analog signal, the analog signal is combined with its added data subcarriers with other program channels of the cable television system via combining network 207 using conventional means known in the art. The output of the combining network is a broadband signal. The output range can range from a 330MHz bandwidth to the currently practical 1GHz limit. An average U.S. cable television system supports approximately sixty television channels (450 MHz).

The output processor 208 will be a power amplifier driving one or more coaxial trunk cables or an optical modulator sending broadband content over fiber optic cables to each of the served neighborhood.

The novelty of the invention is best understood as a measure to combine broadcast television program content with on-demand (private channel) content in a technically feasible and economically practical manner.

Fig. 2a illustrates a particular embodiment in which a centralized recording unit is located at a cable headend to support a "virtual private video recording" function, which is implemented by particular embodiments of the present invention. This functionality enables a cable subscriber to cause broadcast television programs to be temporarily stored for later viewing on a recording device located therein.

A particular number of live television program selections are first selected for processing by a particular embodiment of the present invention, which is illustrated based on the desired service provided by the cable operator. For example, a cable company can decide on all major broadcast networks, and the most popular cable channels (HBO, CNN, MTV, etc.) will be provided as part of the program layer, and subscribers can "pause and resume" the program by utilizing the additional functionality provided by various embodiments of the present invention. This content, which is then sent out of the cable device to the digital set-top box in the subscriber's home, is also made available to the virtual PVR 210 for storage. Local network broadcast programs are sometimes acquired over-the-air in analog format and at other times come from a direct feed of the broadcast studio. When arbitrary content is received in analog format, the content is converted to digital video by the video digitizer 211 before being stored in 210. The virtual PVR 210 records using a sliding time window method in which each program is maintained for a period of time determined by the service provider. In a typical embodiment, the last eight to ten hours of broadcast program content on each channel will be kept available.

The illustrated embodiment of the present invention receives commands from a viewer via cable television return path information 212 a. If the command is to pause a live television program, the set-top box connected to the viewer's television will send back to the headend the program channel currently being viewed by the subscriber. Assuming that the program channel is one of the channels provided by the cable operator for the pause and resume feature, session manager 212 will attempt to find a free private channel path from the headend to the subscriber's set-top box using the channel management subsystem. Assuming an available private channel, the session manager will send a command back to the corresponding subscriber set-top box on a common signaling channel monitored by all set-top boxes using the service. The subscriber's set-top box will be instructed to tune to a particular television channel and decode the dNTSC embedded carrier. The decoded carrier will be decompressed from the compressed digital video signal to a program signal compatible with the subscriber's television set. Thus, the subscriber's set-top box will leave the broadcast channel and be assigned a private television channel with the same programming but now running through a large virtual PVR located at the head end, which the subscriber can manipulate with a remote control in the home as if the device were local.

At the headend, the session manager 212 will address the virtual PVR database 210 to find the specific point in time at which the user requested that the program be paused. A single video frame will be presented to the user via the private television channel provided as described above. When the subscriber wants to resume viewing the paused program, the session manager will instruct the virtual PVR database to replay the program from the point of pause. The subscriber will now watch the program via the private television channel at a point in time that is offset from the live program content. The system can allow any number of pause and resume requests as well as allow the subscriber to fast forward (to the point of the live program, assuming the live program will still be in progress) and rewind until the program is back to the beginning.

An additional novelty of the present invention is the provision of an additional program database 213 to provide long-term storage of favorite programs or movies and to allow recall and playback at a later time, using the private channel mechanism described above.

Neighboring node

One embodiment of using an embedded carrier processor is shown in fig. 3. The equipment is intended to be placed in an equipment rack or suspended from a telephone pole, at each point placed on a cable television system where the optical cable is terminated and the signal is converted to an electrical signal, or at which point the trunk line is tapped and a distribution feed is generated that serves a particular vicinity.

The apparatus described in this figure is placed in line with the distribution cable of a cable television plant and serves some or all of the vicinity served by the fiber optic cable, or some or all of the vicinity served by the tap and feeder cable system (non-fiber, all coaxial equipment) on a conventional trunk. The apparatus extracts a signal through a directional coupler 301 and then applies a low pass filter 302 to remove electrical noise above the highest frequency channel used by the cable television system. The output of the low pass filter is then passed through another directional coupler where the locally generated program channels are added to the main cable broadband channel group. These locally generated channels are typically generated on channels above the highest channel used by the cable television system.

The locally generated channel is established from a signal embedded in the main cable television broadcast channel. The process involves using a standard television tuner device 304 to tune to a television channel containing the desired embedded signal. The output of the tuner is then fed to an embedded data detector 305 which detects the data sub-carriers and feeds the sub-carriers to an embedded data decoder 306 which decodes the embedded data into a binary data transport stream. The demodulated data signal is then provided to a data multiplexer 307 which either simply routes the stream to an available QAM encoder or combines the data stream with another data stream from another embedded carrier and then switches the combined stream to an available QAM encoder. Another path through the device will route a data stream of compressed video information to video decompressor 311, which decompresses the data stream into analog video and modulates the video into an NTSC intermediate signal for up-conversion by 312 to the available frequency. The newly generated television channel can then be viewed by any television and VCR without further processing, which may be used as a solicitation or other advertising channel for on-demand services.

The RF signals generated from the upconverters are then combined by a combining network 310 and then reintroduced to the cable television apparatus through a directional coupler 303. Access to the private channel thus generated is achieved by tuning the existing digital television set-top box converter and cable modem to the newly generated private channel. The private channel generated by the present invention serves subscribers to service within a given neighborhood. Each neighborhood provides the opportunity to reuse the private channel frequency on a neighborhood-by-neighborhood basis, and thus the present invention provides a significant number of private television channels for interactive and on-demand services.

Processor for whole house

An embodiment representing a variation in the system shown in fig. 3 is shown in fig. 4. In this particular embodiment, the present invention uses a single entire room processor (see 112 in the general schematic of FIG. 1) to provide programming to a single subscriber, and will typically be located in or near the building of the cable subscriber. In contrast to the alternative embodiment detailed in fig. 3, where the processor is intended to serve a neighborhood of subscribers (see 107 in the general schematic of fig. 1).

In this embodiment, the tuner 404 tunes to a television channel carrying the desired embedded signal. The embedded data detector 405 extracts the embedded data signal and provides the signal to a video decompression device 406 which then decompresses the video and provides baseband video and audio signals to an NTSC encoder 407 which produces a signal that is modulated onto an RF carrier and combined by 413 with other locally generated RF carriers generated within the entire house module and then added to the house cable distribution by the directional coupler 403. Another path through the entire house module is described by tuner 409 and detector 410 generates an intermediate frequency signal which is then up-converted to a desired channel for output to the cable television system, thereby avoiding decoding and recording steps. This allows for lower cost in the home unit where all signaling is prepared and formatted in advance at the cable head end for direction change at home.

Furthermore, embodiments of the present invention that are used in neighboring nodes can also be used for whole house usage, including the use of re-multiplexing and switching. The whole house decoder allows any television in the home to view on-demand or interactive content without the need for a set-top box. It also facilitates enhanced quality of service internet access to computers located anywhere in the home where cable television system coaxial cable is available.

This embodiment of the present invention provides private television channels on a home-by-home basis, resulting in proportionally more private television channels on a given cable television installation than the neighboring node invention of fig. 3 above. The invention described herein can also be applied to services within a particular cable system service area.

Set top box embodiment

Figure 5 outlines components added to an existing cable set-top box system to allow for the separate decoding of an embedded data stream without the use of an entire house decoder or a neighboring decoder. The figure also illustrates DOCSIS compliant cable modem support. The signal paths from the tuners (505 through 509) are the same as described above. Diplexer 501 accepts a return path signal from DOCSIS cable modem controller 512 for transmission upstream to the cable system headend on a typical return path frequency between 5 and 40 MHz.

System spectrum

Fig. 6 illustrates a typical architecture of a modern cable television system. From left to right, low frequency to high frequency, one cable system uses 5MHz to 35MHz bandwidth for the return path from the home back to the headend. The maximum channel capacity from 52MHz to a particular cable television system (typically 60 channels or 450MHz) is a mix of analog (NTSC) and digital (64 or 256QAM encoded digital transport streams). The lower channel, from channel 2 to about 75% of the downstream capacity, is reserved for analog (NTSC) channels. The remaining 25% is reserved for the digital layer. The present invention places a private, interactive channel on top of the last channel used by the cable television equipment for non-interactive, broadcast channels.

Claims (27)

1. Apparatus for providing programming to a monitor of a user, comprising:

a. a decoder adapted to extract digital information applied to a carrier wave of a television signal in a television channel (analog or digital) of a first cable television system;

b. a modulator adapted to modulate the extracted digital information onto a second cable system television channel as a program; and

c. control circuitry coupled to the decoder and adapted to receive signals from a control device operated by a user, the control circuitry being adapted to determine: (1) which cable system television channel carries said program specified by the user on the control device, and accordingly which cable system television channel constitutes the first cable system television channel, and (ii) which channel serves as the second cable system television channel.

2. The apparatus of claim 1, wherein the monitor is a television.

3. The apparatus of claim 1, wherein the monitor is a computer monitor.

4. The apparatus of claim 1, wherein the first cable television system television channel is analog.

5. The apparatus of claim 1, wherein the first cable television system television channel is digital.

6. Apparatus according to claim 1, wherein the decoder and remodulator form part of a neighbouring node.

7. Apparatus according to claim 1, wherein the decoder and remodulator form part of a home network.

8. The apparatus of claim 1 wherein the decoder and remodulator form part of a set top box.

9. The apparatus of claim 1 wherein the decoder and remodulator are located at a cable television system headend.

10. Apparatus according to claim 1, wherein the remodulator is adapted to feed a cable modem.

11. A method for providing programming to a user's monitor, comprising:

a. extracting digital information applied to a carrier wave of a television signal in a first cable television system television channel (analog or digital);

b. modulating said extracted digital information onto a second cable system television channel as a program, the second channel being available for providing said program to said monitor; and

c. upon receiving a user-specified signal corresponding to the program, determining: (1) which cable system television channel carries the program, and correspondingly which cable system television channel constitutes the first cable system television channel, and (ii) which channel serves as the second cable system television channel.

12. A system for delivering programming to a user monitor, comprising:

a. a source for the program;

b. a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. a modulator adapted to modulate a program onto a carrier, wherein a signal containing the program is substantially orthogonal to the carrier; and

d. a cable television infrastructure adapted to transmit a television signal containing the program so modulated to a plurality of devices adapted to extract the program from the television signal.

13. The system of claim 12, wherein the modulator is adapted to modulate the program onto a visual carrier.

14. The system of claim 12 wherein the program is an interactive program.

15. The system of claim 12 wherein the program is a television program.

16. A system according to claim 12, wherein the system is adapted to receive control signals from user equipment and to change the delivery and display of said program on said user monitor in response to said signals.

17. A system according to claim 12, wherein the system is adapted to vary the timing of delivery and display of said program.

18. A system according to claim 12, wherein the system is adapted to change the content of said program.

19. A system according to claim 12, wherein the system is adapted to receive control signals from a user device and to cause at least a portion of said program to be stored in accordance with said signals.

20. A system according to claim 12, wherein the system is adapted to cause at least a portion of said program to be stored in said source.

21. (PVR) a system for delivering a program to a user monitor, comprising:

a. a source for the program;

b. a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. a modulator adapted to modulate a program onto a carrier, wherein a signal containing the program is substantially orthogonal to the carrier;

d. a cable infrastructure adapted to transmit a television signal containing the program so modulated to a plurality of devices adapted to extract the program from the television signal; and

e. wherein the system is adapted to receive control signals from a user device and to change the transmission and display of said program on said user monitor in accordance with said signals.

22. A system for delivering programming to a user monitor, comprising:

a. a source for the program;

b. a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. a modulator adapted to modulate a program onto a carrier, wherein a signal containing the program is substantially orthogonal to the carrier;

d. a cable infrastructure adapted to transmit a television signal containing the program so modulated to a plurality of devices adapted to extract the program from the television signal; and

e. wherein the system is adapted to receive a control signal from the user equipment and to cause at least a part of said program to be stored in accordance with said signal.

23. A method for delivering programming to a user monitor, comprising:

a. providing a source for a program;

b. providing a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. modulating a signal containing a program onto a visual carrier substantially orthogonal to the visual carrier; and

d. the visual carrier wave onto which the program has been modulated is fed onto the cable infrastructure and conveys the television signal to a plurality of devices adapted to extract the program from the television signal.

24. (PVR TX) a method for delivering a program to a user monitor, comprising:

a. providing a source for a program;

b. providing a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. receiving control signals from a user device and causing at least a portion of said program to be stored in accordance with said signals;

d. modulating a signal containing a program onto a visual carrier substantially orthogonal to the visual carrier; and

e. the visual carrier wave onto which the program has been modulated is fed onto the cable infrastructure and conveys the television signal to a plurality of devices adapted to extract the program from the television signal.

25. The method according to claim 24, wherein modulating the signal containing the program comprises modulating a signal containing a program that has been stored in accordance with the control signal from the user equipment.

26. (PVR TX) a method for delivering a program to a user monitor, comprising:

a. providing a source for a program;

b. providing a source for providing a television signal, wherein the television signal comprises a signal relating to a visual signal and a visual carrier;

c. receiving a control signal from a user device and altering at least a portion of said program in accordance with said signal;

d. modulating a signal containing a program onto a visual carrier substantially orthogonal to the visual carrier; and

e. the visual carrier wave onto which the program has been modulated is fed onto the cable infrastructure and conveys the television signal to a plurality of devices adapted to extract the program from the television signal.

27. The method according to claim 26 wherein modulating the signal containing programming comprises modulating a signal containing programming that has been altered in accordance with a control signal from the user equipment.