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RELATED APPLICATION
U.S. patent application Ser. No. 07/884,515, entitled "Communication
Architecture and Buffer for Distributing Information Services", and filed
on May 15, 1992 concurrently with the present application for A. D.
Gelman, H. Kobrinski, L. S. Smoot, and S. B. Weinstein, is assigned to
Bell Communications Research and contains subject matter related to the
subject matter of the present application.
FIELD OF INVENTION
This invention relates to a store-and-forward communications architecture
and a method for delivering interactive information services.
BACKGROUND OF THE INVENTION
The delivery of information programs, such as video, entertainment, and
educational programs, to large numbers of subscribers has largely been
provided through a few widespread technologies. The most prevalent
technology, which is familiar to most subscribers, is broadcast
television. Under this delivery scheme, television networks, such as CBS,
NBC, ABC, and FOX, and a host of independent broadcasters distribute
pre-scheduled programs to subscribers by broadcasting at radio-frequencies
through the atmosphere. Another commonplace program delivery scheme is
cable television. In a typical cable television system, a variety of
programs are broadcast over a physical medium (such as coaxial and optical
cable), and subscribers who pay for access to the physical medium receive
broadcast programs.
Satellite broadcasting is another technology used to deliver programs to
subscribers. With this technology, programs are broadcast from a central
location via satellite, and subscribers receive the broadcast programs
using large, high-gain antennas often called "satellite dishes". To
receive the programs transmitted from present-day, low-powered satellites,
the subscriber must erect a rather large antenna to provide enough gain
for adequate reception of broadcast programs.
An advantage of the broadcast delivery technologies described above is that
the cost per subscriber is low since the cost of broadcasting programs is
shared among all subscribers. In the case of broadcast television, the
cost to the subscribers for access to programs is free since advertisers
foot the bill. While each of these methods offers a level of convenience
and usefulness, they suffer in that the delivery of video information is
done in a broadcast fashion. Broadcast delivery proves to be inadequate in
many cases to meet the diverse needs of subscribers for information
programs. A major drawback of the broadcast delivery schemes described
above is that subscribers have no direct input on the programs to be
broadcast over the network. Thus, the selection and scheduling of programs
is determined by the network providers and cannot be specifically catered
to meet the needs of individual subscribers. Instead, subscribers must
adjust their schedules around the date and time pre-set by the networks
for airing particular broadcast programs.
Another major shortcoming of conventional broadcasting delivery
technologies is the limited number of program choices offered to
subscribers at once. Subscribers' choices are limited to those programs
being broadcast at the time. Once a subscriber has flipped through the
channels that are receivable within his vicinity, the available choices
have been exhausted. In the case of broadcast television in most
metropolitan areas, the number of program choices is limited to 6 or 7
since only 6 or 7 channels are offered simultaneously in the most commonly
viewed VHF spectrum.
Another limitation of conventional technologies is that broadcast delivery
is not conducive to allowing customer control of the play-out of the
program. In effect, subscribers have little or no opportunity to control
the play-out of the program being viewed in conformance with their special
needs and purposes. Therefore, subscribers are not afforded the
flexibility to fast forward during commercials, to forward past gruesome
scenes, to rewind in order to have missed information instantaneously
repeated, or pause during interruptions. Instead, subscribers must receive
programs substantially as selected, scheduled, and transmitted by the
network.
Realizing these shortcomings of conventional broadcast delivery
technologies, attempts have been made to offer more flexibility to
subscribers. For example, cable television networks offer some programs on
a pay-per-view basis in which customers can tune to special pre-scheduled
programs for an additional cost above and beyond the regular service
charge. Although this added feature allows subscribers access to
additional programs, subscribers still do not have the flexibility of
scheduling start time and date of the program and of interactively playing
out the desired program according to their own needs and desires.
Another attempt to overcome the limitations of conventional broadcast
delivery technologies is the development of a video recorder/transmitter,
which is capable of receiving programs in either compressed or
decompressed format; one such device is described in Audio/Video
Transceiver Apparatus Including Compression R. A. Lang, U.S. Pat. No.
4,963,995, Oct. 16, 1990. This device can receive programs based on
accelerated delivery and permits interactive play-out of the program in
real-time to the subscriber. Although this device overcomes a number of
the shortcomings of conventional broadcast delivery technologies, this
approach is cost-prohibitive for the average subscriber in at least one
embodiment since the device would contain over a gigabit of semiconductor
ram and would currently cost approximately fifty thousand dollars and may
require a downstream communications channel of several hundred megabits
per second (Mb/s) to be connected at the subscriber's premises.
The invention of video-cassette recorders (VCRs) has significantly obviated
some of the shortcomings of conventional broadcast delivery schemes since
this device allows a subscriber to record a broadcast program for later
viewing at a more convenient time. Or if two programs are being broadcast
simultaneously on different broadcast channels, a subscriber can watch one
program and record the other for viewing later. Although the VCR obviates
scheduling constraints of conventional broadcast delivery technologies and
gives subscribers the flexibility to interactively play programs at their
convenience, this device alone has not resolved the drawback of limited
program options available to subscribers.
Video rental stores which offer movies, educational material, games, and
other types of information programs have sprung up to meet the
subscribers' demands for more program options. In exchange for a greater
variety in program choices, a subscriber must endure the inconvenience of
picking up the program from the video rental store and returning it by a
certain date and time.
In view of the shortcomings of conventional broadcast technologies and
ineffective strategies to obviate these shortcomings, it is the object of
our invention to: 1) accommodate subscribers' diverse needs for
information programs from a variety of sources; 2) allow subscribers the
flexibility to access programs on demand to fit their individual
preferences and schedules; 3) provide subscribers with interactive
play-out capabilities; 4) allow access to interactive multi-media
applications such as video games, home shopping, home banking, etc; and 5)
provide an architecture which provides maximal sharing of the information
providers storage resources and the network resources.
SUMMARY OF THE INVENTION
Our invention is a store-and-forward architecture and method for providing
information programs to subscribers on demand. This architecture stores
information programs from single or multiple vendors, forwards segments of
requested programs in high speed bursts, and buffers the segments for
interactive play-out of the requested programs to subscribers in real
time. Our inventive architecture builds upon a broadband network
infrastructure, such as the Broadband Integrated Services Digital Network
(BISDN), and efficiently and economically provides subscribers with
information programs by promoting maximal sharing of the network,
information programs, and storage media while supporting on-demand access.
The major elements of our inventive architecture include: information
warehouses (IWHs), central offices (COs), and customer premises equipment
(CPE). IWHs serve as storage locations where information programs are
archived. The IWHs also store service presentation scripts and program
presentation maps, which are used for managing the play-out of information
programs. Another function of the IWH is to dispense scripts, maps, and
information programs to COs as requested.
In addition to the functions conventionally provided at COs in broadband
networks, COs of our invention also manage subscribers' requests for
information programs based upon associated scripts and maps retrieved from
appropriate IWHs. By employing scripts and maps, the CO can manage
subscribers' requests for information programs without specific knowledge
of the type of service being requested or the content of the information
program. Another function of the CO is to request information programs in
segments comprising all or part of information programs from appropriate
IWHs and buffer the segments once received for play-out to subscribers.
The CPE is the customer's interface to our inventive architecture. At the
CPE, a subscriber places a request for an information program, and the CPE
presents the requested program for use by the subscriber. At this
interface, the subscriber has interactive control of the play-out of
requested information programs.
The CO communicates with IWHs via high speed trunks operating at standard
broadband rates (typically, 155 Mb/s or 622 Mb/s) and with subscribers
over low-speed transmission links operating at rates such as 1.5 Mb/s
downstream and several kilobits upstream for transport of control
information. Information programs are transferred in segments from the
IWHs to COs in a burst mode at transmission rates nominally greater than
real-time, and then these information programs, which are buffered at the
CO, are delivered in real-time from the CO to subscribers' CPEs.
Under our inventive architecture, a dedicated high speed link facility is
not required between a service vendor and a subscriber to provide
on-demand, interactive services. Since programs are delivered from IWHs to
COs in segments at rates typically exceeding real time and due to network
scheduling, our architecture allows information programs to be provided to
subscribers on demand with minimal congestion in the trunk network.
Furthermore, trunk connections between IWHs and COs need only be
maintained long enough to complete the transmission of the segments of the
information program requested, and after the transmission is complete, the
trunk is available to service other requests or for use elsewhere in the
network.
From the subscriber's viewpoint, this architecture offers virtually
unlimited on-demand access to information programs from a wide variety of
vendors without the need of any costly, special hardware for storage and
play-out capabilities as in other proposed alternatives. Furthermore, the
customer will be alleviated from the inconvenience of personally visiting
a program vendor (i.e. a video store) to access a program and returning
the program after use. In addition, the subscriber is not constrained by
the limited program options offered by broadcast networks, and, unlike
broadcast programs, the subscriber has control over the play-out of the
information program.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 depicts the Broadband Integrated Services Digital Network (BISDN) of
the prior art.
FIG. 2 illustrates the store-and-forward architecture for distributing
information programs to subscribers in accordance with an aspect of our
invention.
FIG. 3 depicts a simplified embodiment of our invention comprising three
nodes: an information warehouse; a central office; and customer premises
equipment.
FIG. 4 shows elements of the CO buffers in accordance with an aspect of our
invention.
FIG. 5 depicts a state diagram modeling the presentation script for video
on demand service in accordance with an aspect of our invention.
FIG. 6 depicts an illustrative embodiment of a remote control which may be
employed at the customer premises equipment in accordance with an aspect
of our invention.
FIGS. 7a-7f depict information presented on a subscriber's screen
indicating the function selected and the subscriber's current viewing
position within an information program in accordance with an illustrative
embodiment of our invention.
DETAILED DESCRIPTION
The store-and-forward architecture of our invention facilitates the
delivery of information programs to subscribers. Our architecture is
especially conducive to the delivery of video services on demand; however,
our architecture can support a host of services furnished by multiple
vendors such as the delivery of database materials supplied by a database
material distribution service, electronic magazines furnished by a
magazine clearinghouse, audio programs provided by a music store,
educational programs supplied by a local university, or interactive home
shopping from a home-shopping service. Furthermore, in addition to
providing information programs on-demand, this architecture also supports
broadcast services (such as global pay per view), multicast services (such
as targeted advertising aimed at communities of interest), and narrowcast
(such as individual interactive video games or home banking).
Many network infrastructures may gracefully support the store-and-forward
architecture and method of our invention. For the purpose of a specific
illustrative example, the network infrastructure supporting our
architecture and method is the broadband integrated services digital
network (BISDN), which is projected to be the public switched network of
the future.
Overview of BISDN
The BISDN infrastructure can be characterized as supporting high bandwidth
connections (most advantageously at minimum transfer rates of 155.52 Mb/s)
and rapid connection and disconnection times (times of less than 10
milliseconds are most efficacious). These characteristics make the BISDN
infrastructure particularly suitable for rapidly transmitting bursts of
nominally accelerated information, which our architecture discloses,
through the network. When transmission of a burst of information has been
completed, the network is rapidly freed up to transmit subsequent bursts
of information generated by our inventive architecture or other traffic
being simultaneously supported by BISDN.
FIG. 1 depicts aspects of BISDN of the prior art which provide
interconnectivity for our store-and-forward architecture and method. The
Central Offices (COs) 40 provide the BISDN routing function and are
interconnected using high speed trunks 90, such as fiber optic
transmission trunks. These trunks 90 operate at transmission rates which
are part of a hierarchy of digital rates, each a multiple of the basic
Synchronous Optical Network (SONET) transmission rate defined by the
International Consultative Committee for Telephony and Telecommunications
(CCITT).
This basic SONET transmission rate, referred to as the "STS-1" rate, is
defined to be 51.84 Mb/s. Other rates in the hierarchy are defined as
STS-N, where N is the whole number multiplier of the STS-1 rate. For
example STS-3 would be equal to 155.52 Mb/s. BISDN typically employs
Asynchronous Transfer Mode (ATM) techniques. In this technique, data is
routed from point-to-point within the network in self-contained,
fixed-length packets of data called "cells". The standard cell for
Broadband transmission systems has been defined by the CCITT to be 53
octets in length with five octets dedicated to header information such as
destination addressing information for the packet and other labeling
functions.
BISDN employs ATM switching equipment 39 in the COs 40. These switching
systems route cells from an originating site within the broadband network
to a destination with connection establishment times of a few
milliseconds. It is thus possible to send bursts of high-speed digital
information from one location in the network to another. Once a cell has
been routed through the network, a following cell or group of cells can be
routed to the same or other locations in the network.
Detailed Description of Inventive Communications Architecture
The major components of our inventive architecture, as shown in FIG. 2,
include a plurality of Information Warehouses (IWHs) 10, a plurality of
Central Offices (COs) 40, and a plurality of customer premises equipment
(CPE) 70. Each IWH 10 may be connected to multiple COs 40 via high speed
trunks 90 operating at standard broadband rates (typically SONET rates of
approximately 155 Mb/s or 622 Mb/s). Multiple COs are also interconnected
by high speed trunks 90. Each CO 40 may serve subscribers at multiple CPEs
70 via transmission links 91 operating bidirectionally at low-speed rates,
such as 1.5 Mb/s downstream and a few kilobits/second upstream.
The asymmetrical digital subscriber line (ADSL) can advantageously be
employed as the transmission link 91. ADSL is known in the communications
industry as a mechanism for providing bi-directional transport from a
node, such as the CO, to a subscriber at 1.5 Mb/s, downstream, and a few
kilobits/second, upstream, overlaid on a telephony channel. In our
architecture, information programs are transferred in segments from
storage at the IWHs 10 to COs 40 in high speed bursts at rates typically
much faster than real-time. The information programs are then buffered at
the COs 40 and delivered in real-time from the COs 40 to subscribers' CPE
s 70.
For illustrative purposes, FIG. 3 depicts a three node architecture
comprising an IWH 10, a CO 40, and a CPE 70 specifically to show the
interconnection and internal structure of these nodes. The IWH 10 archives
information programs from a single or multiple vendors and stores related
service presentation scripts and program presentation maps to manage the
play-out of the information programs. As shown in FIG. 3, the IWH 10 is
comprised of an IWH service processor (IWH-SP) 11, archival storage 12, an
IWH control bus (IWH-CBUS) 13, on-line storage 14, an IWH control and data
interface (IWH-IF) 15 and an IWH data bus (IWHDBUS) 16.
The IWH-SP 11 manages and schedules the distribution of requested
information, such as scripts, maps, and information programs, from the IWH
10 in response to requests from the CO 40. The IWH-SP 11 also controls the
retrieval of information from archival storage 12, which is the IWH's
long-term storage, to online storage 14, which temporarily stores
information for ready access and transport to the CO 40.
The IWH-IF 15 is the interface for the IWH 10 to the network. The IWH-IF 15
receives requests from the CO 40 via trunk 90 and routes these requests to
the IWH-SP 11 for processing. Furthermore, information dispensed from the
IWH 10 to the CO 40 is sent via the IWH-IF 15. Communications of control
information between elements of the IWH 10 are transported via the
IWH-CBUS 13, while communication of data, such as segments of information
programs, are transported via the IWHDBUS 16.
The CO 40 of our invention manages subscribers' requests for information
programs. To support this management function the CO 40 employs, as shown
in FIG. 3, a CO service processor (CO-SP) 41, a CO control and data
interface (CO-IF) 45, a CO control bus (CO-CBUS) 43, a CO data bus
(CO-DBUS) 46 and CO buffers 44. In response to subscribers request for
service, the CO-SP 41 queries the IWH 10 for the appropriate script, map,
and information program. Furthermore, the CO-SP 41 manages the
dissemination of scripts, maps, and information programs to the
appropriate CO buffer 44.
The CO-IF 45 is the CO's interface to the trunk network 90 which connects
to the IWH 10. Requests from the CO-SP 41 to the IWH 10 for scripts, maps,
and segments of information programs from the IWH on-line storage 14 to be
downloaded into a CO buffer 44 are delivered through the CO-IF 45. CO
buffers 44 receive and process subscribers requests and also store
segments of an information program requested by a subscriber for immediate
play-out. Also, the CO buffers manage the presentation of the requested
information program to the subscriber and support the subscriber's
capability to interactively control play-out of the information program.
Each CPE may have a dedicated buffer solely for the subscriber's use, or a
buffer may be dynamically allocated to the subscriber at the time a
request for service is made. For illustrative purposes, we assume that one
of the buffers 44 is designated to CPE 70 as depicted in FIG. 3, and
likewise, one buffer is designated to each CPE. A more detailed discussion
of the CO-buffer design and operation is provided below. Segments of
information programs are transported from the CO-IF 45 to the CO buffers
44 via the CO-DBUS 46. Control information, including scripts and maps, is
transported between elements of the CO 40 via the CO-CBUS 43.
The CPE 70 is the subscriber's interface to the network. At the CPE 70, the
subscriber places requests for information programs and interactively
controls the play-out of information programs. As shown in FIG. 3, the CPE
70 is comprised of a user network interface (UNI) 71, a user control
interface (UCI) 72, a graphics overlay processor 74, and a decoder 73.
Subscriber's requests are generated at the UCI 72. As illustratively shown
in FIG. 3, the UCI 72 could be operated remotely, thereby allowing the
subscriber to make requests or input interactive control signals by remote
control 75, which is shown in greater detail in FIG. 6.
The UNI 71 receives the subscriber's request for an information program or
interactive control signal generated at the UCI 72 and transmits this
information to the CO buffer 44 designated to the subscriber via
transmission link 91. Furthermore, the UNI 71 receives the requested
information program from the CO buffer 44 in real-time via transmission
link 91. The graphics overlay processor 74 receives signalling information
through the UNI 71 via trunk 91 from CO buffer 44. This signalling
information controls the overlay of text and graphics on the information
program played to the subscriber. Upon receiving the information program,
the UNI 71 passes the program to the decoder 73, where the program is
decoded to it original signal form (e.g. analog) for use by the
subscriber.
Detailed Description of Inventive CO-Buffer System
As shown in FIG. 3, the CO buffer system is comprised of a cluster of 1 to
N CO buffers 44. Each cluster of N CO buffers would nominally reside in a
multi-shelf frame supported by CO-CBUS 43 and CO-DBUS 46. A cluster of N
CO buffers is supervised by the CO-SP 41, which communicates to the BISDN
network via the CO-IF 45.
A detailed illustration of the components of a CO buffer is shown in FIG.
4. Each CO buffer connects its designated subscriber to the communications
architecture and receives and processes the subscriber's requests.
Additionally, the CO buffer requests segments of an information program
desired by the subscriber based upon instructions in the script and
according to the map corresponding to the information program. Since data
is received at the CO buffer in bursts at rates typically much higher than
real time and play-out to the subscriber is in real-time, the CO buffer
also provides rate conversion and smoothing functions. Other functions of
the CO buffer system include managing the play-out of the requested
information program to the subscriber and supporting the subscriber's
capability to interactively control play-out of the information program.
To perform these functions, a CO buffer comprises a buffer operating system
406 for providing basic operating functions of the buffer. The CO buffer
also comprises interfaces for providing external access to the CO buffer,
processors for managing and administering the internal operations of the
CO buffer, busses for providing internal transport of data and control
signals between components of the CO buffer, and buffers and storage
memory for storing segments of the information program and its associated
script and map. Specifically, the subscriber line interface 401 links the
CO buffer to its designated subscriber CPE 70 via transmission link 91.
A variety of subscriber line interfaces can be employed depending upon the
types of services being provided to the subscriber and the upstream and
downstream bandwidth capabilities required by the subscriber.
Illustratively, the Asymmetrical Digital Subscriber Line (ADSL) interface
may be suitable for cases such as video-on-demand delivery where the
downstream bandwidth is relatively large (on the order of 1 to a few Mb/s)
and the upstream signalling requirements are modest (ranging up to a few
tens of kilobits/second). An ADSL interface would also support a normal
telephonic channel which would allow the subscriber to receive normal
telephone service as well as information programs, (such as
video-on-demand), via the same transmission link 91.
Alternatively, a High Speed Digital Subscriber Line (HDSL) interface could
be employed where bi-directional, moderately high-speed transmission is
required in both the upstream and downstream directions. Different
interfaces could be employed without substantially effecting the operation
and components of the CO buffer 44 or the CO 40.
Other interfaces include the CO-CBUS interface 408, which links the CO
buffer to the CO-CBUS 43, and the CO-DBUS interface 409, which links the
CO buffer to the CO-DBUS 46. The script and map associated with the
information program are passed via the CO-CBUS 43 to the CO-CBUS interface
408 and then passed via the buffer CBUS 412 to the script storage 407 and
map storage 413 where the script and map are stored, respectively.
Segments of the information program received from the IWH are passed via
the CO-DBUS 46 to the CO-DBUS interface 409 and then passed via the buffer
DBUS 411 to buffer-1 403 or buffer-2 404 where segments are stored.
Segments of the information program can be received at and played out from
both buffer-1 403 and buffer-2 404 in a ping-pong (i.e., alternating)
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