U.S. patent application number 10/731310 was filed with the patent office on 2004-09-02 for home network for ordering and delivery of video on demand, telephone and other digital services.
Invention is credited to Fish, Ronald Craig, Rakib, Selim Shlomo.
Application Number | 20040172658 10/731310 |
Document ID | / |
Family ID | 23921084 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040172658 |
Kind Code |
A1 |
Rakib, Selim Shlomo ; et
al. |
September 2, 2004 |
Home network for ordering and delivery of video on demand,
telephone and other digital services
Abstract
A gateway for coupling a local area network coupled to a
plurality of peripheral devices at a customer premises to one or
more external networks that deliver analog signals bearing analog
video such as regularly scheduled CATV, terrestial or satellite
C-band broadcasts, or modulated with digital video-on-demand data,
or IP packets bearing IP telephony data or data from the internet.
The preferred construction is modular so that single expansion
modules to interface only to DSL lines or only to a satellite dish
or only to HFC, or some combination thereof may be added as needed.
The gateway may be a standalone circuit also with hardwired
interfaces to one or more external network types. The incoming
analog signals are either digitized, compressed and distributed on
the local area network or the digital data thereon is recovered and
packetized as an IP packet if not already so packetized and
distributed via a router process to the device that requested the
data via the local area network.
Inventors: |
Rakib, Selim Shlomo;
(Cupertino, CA) ; Fish, Ronald Craig; (Morgan
Hill, CA) |
Correspondence
Address: |
Ronald Craig Fish
Ronald Craig Fish, A Law Corporation
P.O. Box 2258
Morgan Hill
CA
95038
US
|
Family ID: |
23921084 |
Appl. No.: |
10/731310 |
Filed: |
December 8, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10731310 |
Dec 8, 2003 |
|
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09483681 |
Jan 14, 2000 |
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Current U.S.
Class: |
725/120 ;
348/E7.069; 725/111; 725/119; 725/78; 725/82 |
Current CPC
Class: |
G08B 13/19667 20130101;
H04L 69/169 20130101; H04N 21/222 20130101; G08B 13/19658 20130101;
G08C 2201/41 20130101; H04L 69/08 20130101; H04N 21/43615 20130101;
H04L 29/06 20130101; H04L 2012/6424 20130101; H04N 7/173 20130101;
H04L 12/66 20130101; H04L 69/16 20130101; H04L 69/168 20130101;
H04N 21/2665 20130101; H04L 12/6418 20130101; G08B 13/19656
20130101; H04B 7/18584 20130101; H04L 12/2801 20130101 |
Class at
Publication: |
725/120 ;
725/119; 725/078; 725/082; 725/111 |
International
Class: |
H04N 007/18; H04N
007/173 |
Claims
What is claimed is:
1. A gateway apparatus comprising: a host computer having a host
bus; one or more local area network interfaces coupling said host
computer to one or more local area networks than carry data between
said gateway and one or more devices located within a customer
premises; one or more external network interface circuits coupled
to said host bus for interfacing said host computer to one or more
networks external to said customer premises which deliver analog
and/or digital video and other digital data to said customer
premises; and wherein said host computer is programmed to implement
an IP packetization process to receive data from said external
network interface circuits and packetize it into IP packets, and
programmed with a routing process to receive IP packets from said
IP packetization process and encapsulate them into local area
network packets and transmit them on the appropriate local area
network via one or more of said local area network interfaces and
for receiving local area network packets from devices coupled to
said local area networks and stripping off the local area network
packet headers and routing the encapsulated IP packets to the
appropriate external network interface circuit for transmission
over an external network, and a management and control process for
receiving requests for data from said devices coupled to said local
area networks and sending digital control data to said external
network interface circuits to control them to obtain said data.
2. The apparatus of claim 1 wherein said IP packetization process
controls said host computer to receive data from said one or more
external network interface circuits which is not already in the
form of an internet protocol packet and packetizing said data into
an internet protocol formatted packet addressed to a device coupled
to one or more of said local area networks.
3. The apparatus of claim 1 wherein said routing process controls
said host computer to receive internet protocol formatted packets
either from said IP packetization process or directly from an
external network interface circuit and, with said network
interface, look up the Ethernet address of the device coupled to
said local area network that corresponds to the internet protocol
packet's destination address, and do all the protocol conversions
necessary to encapsulate each said internet protocol packet into
one or more Ethernet local area network packets addressed to a
device which requested data in said internet protocol packet and
transmit same over the appropriate local area network to the device
which requested said data, and further controls said host computer
to receive Ethernet packets from devices coupled to said local area
networks that include internet protocol packets via said local area
network interface(s) and do all the protocol conversions necessary
to strip off the Ethernet packet header and route the encapsulated
internet protocol packet to the appropriate external network
interface circuit for transmission on an external network to the
server to which the internet protocol packet is addressed.
4. The apparatus of claim 1 wherein said management and control
process is structured to control said host computer to receive
Ethernet packets from devices coupled to said local area network(s)
which contain requests to download specific web pages at URLs
identified in said packet or to receive and distribute regularly
scheduled video broadcasts over a CATV hybrid fiber coaxial cable
system, a satellite downlink or a terrestial broadcast, or to
request a video program to be delivered over said CATV hybrid fiber
coaxial cable system or said satellite downlink or via a digital
subscriber line local loop, and generating and sending appropriate
control data to the appropriate one of said external network
interface circuits to cause the requested data or video broadcast
or video-on-demand program to be received.
5. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a digital subscriber line
modem.
6. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a conventional POTS line fax
and/or data modem.
7. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises an internet packet telephony
circuit to interface said gateway to plain old telephone service
and/or digital subscriber line phone lines from a public service
telephone network central office.
8. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a private branch exchange
(PBX) telephony circuit for interfacing said gateway to one or more
plain old telephone service (POTS) telephone lines which are
internal or external to said customer premises and/or one or more
digital subscriber line (DSL) phone lines from a public service
telephone network central office, said PBX telephony circuit
including a switch controlled by a plurality of processes
controlling said host computer to implement PBX telephony functions
for line devices such as telephones coupled to said one or more
POTS or DSL lines or to said local area netork, said processes
including a PBX application process, one or more processes
implementing a TAPI dynamic linked library and a PBX card driver
process.
9. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a cable modem for interfacing
said gateway to a CATV hybrid fiber coaxial cable system
connection.
10. The apparatus of claim 9 wherein said cable modem is compatible
with the DOCSIS 1.2 national standard for cable modems as that
standard existed as of the filing date of this patent
application.
11. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a CATV hybrid fiber coaxial cable system
connection, said receiver capable of receiving and demodulating and
recovering digitized, compressed video-on-demand program data
modulated onto a downstream carrier requested by a device coupled
to said local area network and demultiplexing the audio and video
components and transmitting the recovered data to said IP
packetization process via said host bus.
12. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a CATV hybrid fiber coaxial (HFC) cable system
connection, said receiver capable of receiving analog video
transmissions on said HFC requested by a device coupled to said
local area network and digitizing and demodulate said analog video
transmissions and then encoding the resulting data into a format in
which it can be compressed, and then compressing the data and
transmitting it via said host bus to said IP packetization
process.
13. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a satellite dish and receiving compressed digital
data encoding a regularly scheduled television program modulated
onto a downlink carrier requested by a device coupled to said local
area network and demodulating and recovering said digital data and
demultiplexing the audio and video data therefrom and transmitting
said recovered digital data via said host bus to said IP
packetization process.
14. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a satellite dish and receiving compressed digital
data encoding a video-on-demand television program modulated onto a
downlink carrier requested by a device coupled to said local area
network and demodulating and recovering said digital data and
demultiplexing the audio and video data therefrom and transmitting
said recovered digital data via said host bus to said IP
packetization process.
15. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a satellite dish and receiving analog regularly
scheduled television programs modulated onto a downlink carrier
requested by a device coupled to said local area network and
demodulating and digitizing said television signals and encoding
the digital data into a format that can be compressed and
compressing said digital data and transmitting said compressed
digital data via said host bus to said IP packetization
process.
16. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a satellite dish and receiving digital data
encoding a web page or other information from the internet and
encapsulated into internet protocol packets requested by a device
coupled to said local area network and that have been modulated
onto a downlink carrier and demodulating and recovering said
internet protocol packets and transmitting them via said host bus
to said routing process.
17. The apparatus of claim 1 wherein said one or more external
network interface circuits comprises a receiver for interfacing
said gateway to a conventional terrestial broadcast television
antenna and receiving a regularly scheduled television program
signal requested by a device coupled to said local area network and
modulated onto a terrestial broadcast carrier and demodulating said
signals digitizing said signals and encoding the digital data into
a format that can be compressed and compressing the digital data
and transmitting said compressed digital data via said host bus to
said IP packetization process. TER-008 claims #2.
18. A gateway apparatus comprising: a host computer having a host
bus; one or more local area network interface means for coupling
said host computer to one or more local area networks than carry
data between said gateway and one or more devices located within a
customer premises; one or more external network receiver means
coupled to said host bus for interfacing said host computer to one
or more networks external to said customer premises by receiving
analog signals and digitizing and compressing them and supplying
the compressed data to said host computer or receiving and
recovering video and other data in digital form which has been
modulated onto a dowstream carrier for transmission to said
customer premises and supplying the recovered digital data to said
host computer; one or more external network transceiver means
coupled to said host bus for interfacing said host computer to one
or more networks external to said customer premises by receiving
analog signals and digitizing and compressing them and supplying
the compressed data to said host computer or receiving and
recovering video and other data in digital form which has been
modulated onto a dowstream carrier for transmission to said
customer premises and supplying the recovered digital data to said
host computer and include an upstream transmitter for receiving
digital data from said host computer and transmitting it outbound
on an external network; and wherein said host computer is
programmed to implement an IP packetization process to receive data
from said external network interface circuits and packetize it into
internet protocol (IP) formatted packets, and programmed with a
routing process to receive IP packets from said IP packetization
process and encapsulate them into local area network packets and
transmit them on the appropriate local area network via one or more
of said local area network interfaces and for receiving local area
network packets from devices coupled to said local area networks
and stripping off the local area network packet headers and routing
the encapsulated IP packets to the appropriate external network
interface circuit for transmission over an external network, and an
IP telephony and other processes to control said host computer to
control line devices coupled to standard or DSL telephone lines or
local area networks coupled to said gateway or line devices and
other external network interface circuits coupled to said host
computer via said host bus to implement IP telephony functions, and
a management and control process for receiving requests for data
from said devices coupled to said local area networks and sending
digital control data to said external network interface circuits
and/or line devices to control them to obtain said data.
19. The apparatus of claim 1 18 wherein said one or more local area
network interface means are Ethernet local area network interface
cards and wherein said routing process controls said host computer
to receive internet protocol formatted packets either from said IP
packetization process or directly from an external network
interface circuit and, with said network interface, look up the
Ethernet address of the device coupled to said local area network
that corresponds to the internet protocol packet's destination
address, and do all the protocol conversions necessary to
encapsulate each said internet protocol packet into one or more
Ethernet local area network packets addressed to a device which
requested data in said internet protocol packet and transmit same
over the appropriate local area network to the device which
requested said data, and further controls said host computer to
receive Ethernet packets from devices coupled to said local area
networks that include internet protocol packets via said local area
network interface(s) and do all the protocol conversions necessary
to strip off the Ethernet packet header and route the encapsulated
internet protocol packet to the appropriate external network
transceiver means for transmission on an external network to the
server to which the internet protocol packet is addressed.
20. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises a private branch exchange (PBX)
telephony means for interfacing said gateway to one or more plain
old telephone service (POTS) telephone lines which are internal or
external to said customer premises and/or one or more digital
subscriber line (DSL) phone lines from a public service telephone
network central office, said PBX telephony means including a switch
controlled by a plurality of processes controlling said host
computer to implement PBX telephony functions for line devices such
as telephones coupled to said one or more POTS or DSL lines or to
said local area netork, said processes controlling said host
computer including a PBX application process, one or more processes
implementing a TAPI dynamic linked library and a PBX card driver
process.
21. The apparatus of claim 18 wherein said management and control
process is structured to control said host computer to receive
Ethernet packets from devices coupled to said local area network(s)
which contain requests to download specific web pages at URLs
identified in said packet or to receive and distribute regularly
scheduled video broadcasts over a CATV hybrid fiber coaxial cable
system, a satellite downlink or a terrestial broadcast, or to
request a video program to be delivered over said CATV hybrid fiber
coaxial cable system or said satellite downlink or via a digital
subscriber line local loop, and generating and sending appropriate
control data to the appropriate one of said external network
transceiver means to cause the requested data or video broadcast or
video-on-demand program to be received.
22. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises a digital subscriber line modem
means for interfacing said gateway to a digital subscriber line
local loop.
23. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises a conventional POTS line fax
and/or data modem means for interfacing said gateway to said
conventional POTS telephone line to the central office of the
public service telephone network.
24. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises an internet packet telephony
means for interfacing said gateway to plain old telephone service
and/or digital subscriber line phone lines from a public service
telephone network central office.
25. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises a cable modem means for
interfacing said gateway to a CATV hybrid fiber coaxial cable
system connection.
26. The apparatus of claim 25 wherein said cable modem is
compatible with the DOCSIS 1.2 national standard for cable modems
as that standard existed as of the filing date of this patent
application.
27. The apparatus of claim 18 wherein said one or more external
network transceiver mean comprises means for interfacing said
gateway to a CATV hybrid fiber coaxial cable system connection to
request a specified video-on-demand program via an upstream message
and for receiving and demodulating and recovering digitized,
compressed video-on-demand program data modulated onto a downstream
carrier requested by a device coupled to said local area network
and demultiplexing the audio and video components and transmitting
the recovered data to said IP packetization process via said host
bus.
28. The apparatus of claim 18 wherein said one or more external
network receiver means comprises means for interfacing said gateway
to a CATV hybrid fiber coaxial (HFC) cable system connection to
make said gateway capable of receiving analog video transmissions
on said HFC requested by a device coupled to said local area
network and digitizing and demodulating said analog video
transmissions and then encoding the resulting data into a format in
which it can be compressed, and then compressing the data and
transmitting it via said host bus to said IP packetization
process.
29. The apparatus of claim 18 wherein said one or more external
network receiver means comprises a means for interfacing said
gateway to a satellite dish and receiving compressed digital data
encoding a regularly scheduled television program modulated onto a
downlink carrier requested by a device coupled to said local area
network and demodulating and recovering said digital data and
demultiplexing the audio and video data therefrom and transmitting
said recovered digital data via said host bus to said IP
packetization process.
30. The apparatus of claim 18 wherein said one or more external
network transceiver means comprises a conventional modem means for
making a dialup connection to a satellite uplink facility or video
server and sending a message requesting delivery of a specified
video-on-demand selection, and receiver means for interfacing said
gateway to a satellite dish and receiving compressed digital data
encoding a video-on-demand television program modulated onto a
downlink carrier requested by a device coupled to said local area
network and demodulating and recovering said digital data and
demultiplexing the audio and video data therefrom and transmitting
said recovered digital data via said host bus to said IP
packetization process.
31. The apparatus of claim 18 wherein said one or more external
network receiver means comprises means for interfacing said gateway
to a satellite dish and receiving analog regularly scheduled
television programs modulated onto a downlink carrier requested by
a device coupled to said local area network and demodulating and
digitizing said television signals and encoding the digital data
into a format that can be compressed and compressing said digital
data and transmitting said compressed digital data via said host
bus to said IP packetization process.
32. The apparatus of claim 18 wherein said one or more external
network receiver means comprises means for interfacing said gateway
to a satellite dish and receiving digital data encoding a web page
or other information from the internet and encapsulated into
internet protocol packets requested by a device coupled to said
local area network and that have been modulated onto a downlink
carrier and demodulating and recovering said internet protocol
packets and transmitting them via said host bus to said routing
process.
33. The apparatus of claim 18 wherein said one or more external
network receiver means comprises means for interfacing said gateway
to a conventional terrestial broadcast television antenna and
receiving a regularly scheduled television program signal requested
by a device coupled to said local area network and modulated onto a
terrestial broadcast carrier and demodulating said signals
digitizing said signals and encoding the digital data into a format
that can be compressed and compressing the digital data and
transmitting said compressed digital data via said host bus to said
IP packetization process.
34. A gateway apparatus comprising: a host bus; a plurality of
expansion card connectors electrically coupled to said host bus;
one or more expansion module printed circuit boards coupled to said
host bus through one or more of said expansion card connectors,
each expansion module including the appropriate circuitry to
receive signals from an external network media comprised of either
a hybrid fiber coaxial cable of a CATV system, a digital subscriber
line local loop, an analog plain old telephone service line or a
satellite dish, and to either recover digital data transmitted via
said external network media or to receive analog signals
transmitted via said external network media and generate digital
data therefrom, and, depending upon the type of external network
media to which each expansion module is coupled, to also transmit
digital data modulated on a carrier signal out on said external
network media; one or more network interface adapters for coupling
said gateway to one or more local area networks which convey
digital data throughout a customer premises; an a host computer
having a central processing unit or microprocessor coupled to said
host bus and programmed to perform at least a management and
control process to receive requests tranmitted TRANSMITTED from
users to said gateway via one or more of said local area networks
for data or video or audio programs transmitted on a regularly
scheduled or on-demand basis on one of said external network media
and to react thereto by appropriately controlling said one or more
expansion modules via data transmitted over said host bus to
retrieve the requested data or video or audio program, and
programmed to perform an IP packetization process to receive
digital data from one or more of said expansion modules and said
management and control process and encapsulate said data into an
internet protocol packet addressed to the device on a local area
network coupled to said gateway which requested said data, and
programmed to perform a routing process to receive network packets
containing internet protocol packets and to strip off the network
packet header and to route said internet protocol packet to the
appropriate expansion module for upstream transmission on a
external network media and to receive internet protocol packets
from one or more of said expansion modules or said IP packetization
process and to look up the IP destination address and map it to a
local area network address corresponding thereto and encapsulate
the internet protocol packet in a local area network packet
addressed to the device owning said IP destination address and
route it to said device via the appropriate network adapter, and
programmed with one or more IP telephony and/or PBX and/or other
telephony enabled application programs to implement IP telephony
and/or PBX functions through a TAPI dynamic linked library of
programs which control said host computer to carry out standard and
advanced telephony functions which can be invoked through a
standard TAPI application programmatic interface and one or more
telephony service provider programs and/or PBX expansion module
programs which convert messages from one or more TAPI library
programs to digital data sent over said host bus to one or more of
said expansion modules to carry out one or more telephony
functions.
35. A network adapter for coupling a conventional television to a
local area network, comprising: a network interface circuit having
an input coupled to a local area network and having an output at
which digital data encoding a compressed video appears and
functioning to receive local area network packets encapsulating
internet protocol format packets but only outputting internet
protocol format packets encapsulated in local area network packets
addressed to this particular network interface circuit; means for
receiving infrared or radio frequency commands and data from a
wireless remote control or a wireless keyboard and for packetizing
the data and commands into packets suitable for transmission over
said local area network; an internet protocol video circuit coupled
to said network interface circuit for receiving internet protocol
format packets from said network interface circuit and determining
if the packet contains video or graphics data and stripping off the
internet protocol format header and outputting graphics data at a
graphics data output and outputting video data at a video data
output; a decompression circuit coupled to said video data output
for decompressing the video data and outputting uncompressed video
data in a YUV format at a first output and uncompressed audio data
at second output; an audio processor means coupled to receive said
uncompressed audio data and process it to convert it to an analog
audio signal; a graphics circuit coupled to said graphics output
for receiving graphics data and generating graphics data signals at
a graphics output; means coupled to receive said uncompressed video
data and said graphics data signals and process both said graphics
data signals and said uncompressed video data into NTSC, PAL or
SECAM or composite format analog video signal which can be
displayed on a television if coupled to a video input of said
television; and optionally, a video modulator for receiving said
analog video signal and said analog audio signal and modulating
them onto an radio frequency carrier at the frequency of a locally
unused channel.
Description
FIELD OF USE
[0001] The invention finds applicability in the distribution of
digital video on demand services and other digital services
throughout a consumer's location.
[0002] With the advent of cable modems, there is the ability to
deliver digital data at high rates from content providers and the
internet over cable TV systems. Many different services will be
delivered digitally, one of which is video on demand and high
definition TV digital data. Another digital service which is useful
at least for business establishments is video conferencing. Other
digital services that will be becoming more and more useful in the
future are high speed contact with the corporate LAN from home for
telecommuters, high speed internet access, distance learning,
multimedia presentations to remote and/or dispersed audiences,
etc.
[0003] The development of cable modems has enabled the delivery of
high speed data over 10 MB/sec channels to customer premises over
hybrid fiber coaxial cable TV distribution networks. But once the
digital data reaches a customer premises, it still must be
distributed and converted to a proper format for use by the user on
a TV, a telephone, a video phone, a computer, a network computer a
FAX, a DVD recorder and other peripherals that will be developed in
the future.
[0004] Concurrently, the telephone companies have developed digital
subscriber line technologies such as Asymmetrical Digital
Subscriber Line (ADSL), High Bit Rate Digital Subscriber Line
technology, ISDN and ISDL, Rate Adaptive Digital Subscriber Line
(RADSL), Symmetric Digital Subscriber Line (SDSL), Very High Speed
DSL (VDSL). These different technologies are described in Muller,
Desktop Encyclopedia of Telecommunications, p. 93-95 (McGraw Hill
1998) ISBN 0-07-044457-9, and Clayton, Illustrated Telecom
Dictionary, (McGraw Hill 1998) ISBN 0-07-012063-3, and Horak,
Communications Systems and Networks, Voice, Data and Broadband
Technologies, (M&T Books, Foster City, Calif. 1997) ISBN
1-55851-485-6, the entirety of all these publications being hereby
incorporated by reference. These digital subscriber line
technologies will soon be capable of delivering digital voice, data
and image information from various servers as well as via high
speed internet access to the subscriber premises over standard
telephone copper twisted pairs which are already in the ground and
which everybody already has. Some of these technologies are fast
enough to also deliver video on demand, which typically requires
about 2 megabits/sec data rate.
[0005] The also were introduced in 1994, digital broadcast
satellite services (DBS) such as DirecTV (offered by Hughes
Electronics and Thomson Multimedia). DBS services already can or
soon will provide video on demand, internet connectivity and
multimedia applications all with the high picture quality that
digital technology provides. Video conferencing via DirectPC
service may also soon be provided. DirecTV delivers 175 channels of
digital-quality programming through an 18 inch dish antenna, a
digital set-top decoder box and a remote control. An access card
allows billing information to be captured by the set-top decoder
box and downloaded by the PSTN to a billing center for pay-per view
programs ordered by a user. In addition, DirecPC technology allows
high speed (400 KB/sec) internet access to PCs in the customer
premises using the DBS dish and coaxial cable distribution network.
An expansion card couples the PC's I/O bus to the coaxial cable
distribution network of the DBS system. A modem is used by the PC
to make a dial up connection to the internet service provider (ISP)
which then sends internet data to the PC via an uplink to the
satellite and then down to the user's dish.
[0006] One problem that consumers of digital data delivery services
will soon face is as follows. There is great uncertainty as to
which subscription data delivery services will provide the most
reliable, best performing and least expensive version of each type
service. Thus, there is a need for a way for a user to be able to
couple to all the different subscription service data delivery
options available to her and to distribute the data cheaply
throughout her premises to all the different peripherals that need
it like television sets, computers, telephones, video phones etc.
To do this, it will be necessary to have some sort of circuit that
can interface with all the different subscription service digital
data delivery networks and at least one local area network running
throughout the user's home and do any necessary protocol
conversions and packet, cell or frame reassembly and encapsulation
into packets of the type used on the LAN.
[0007] ADSL routers such as the Remote 810 ADSL Router manufactured
by 3Com currently exist. These routers can couple an Ethernet local
area network to ADSL lines so that POTS voice conversations can
occur simultaneously while searching the internet. The Remote 810
ADSL Router has an integrated 4-port 10Base-T hub to couple
multiple PCs can share the same ADSL line. The router supports up
to 16 simultaneous concurrent connections to multiple destinations
on the internet and can perform bridging functions. 3Com also
manufactures SDSL routers like the OfficeConnect Remote 840 SDSL
which can support applications that require high bandwidth in both
directions such as video conferencing, remote training, Web
hosting, e-commerce and other multimedia applications.
[0008] Other prior art, such as the 3Com PathBuilder S700 WAN
switch, exists which concentrates, aggregates and switches traffic
over wide area networks. The PathBuilder S700 WAN can converge
voice, video and data applications--including Frame Relay, ATM and
SONET--onto a common network. Up to 100 interfaces are supported.
Advanced traffic management features such as traffic shaping,
priority queuing and multicasting, guarantee the right amount of
bandwidth for each application and let you build and manage your
WAN infrastructure. The switch features a future-proof chassis with
a modular construction to protect the initial investment and
provide a migration path to accomodate future growth. The switch
has individual application modules that provide native interfaces
to a variety of campus networking technologies such as LANs, muxes,
routers, SNA applications, business video and PBXs. Each
application module adapts communications traffic to the cell-based
backplane and transports it across the PathBuilder S700 switch cell
bus to the appropriate trunk interface connections which offer a a
comprehensive range of campus and wide area interface types. A
T1/UNI module supports Inverse Multiplexing for ATM at speeds
ranging from 1.5 Mbps to 16 Mbps. An 18-slot chassis supports
migration to T3/E3 or OC-3 services as bandwidth requirements
increase. Distributed processing implemented by placing a RISC
processor on each application module to provide scaleable
performance and wire speed communications.
[0009] However, the 3COM Pathbuilder S700 WAN Switch lacks the
capability to interface with ADSL lines, cable modems, satellite
dishes, wireless local loops, terrestial microwave links or other
subscription network services that may become available in the
future such as digital data delivery over the power lines. The 3COM
Pathbuilder S
[0010] 700 WAN Switch is a professional level switch which is not
affordable for the average home network consumer. In short, it is
believed that no gateways or routers currently exist which can
couple a local area network such as an Ethernet to each of the
public service telephone network, and which embody and combine the
technology of ADSL modems, cable modems, and satellite DirectPC
decoder boxes with IP video and IP telephony interfaces and
switching, routing and protocol conversion capability.
[0011] In the current climate of deregulation, fierce competition
for provision of telecommunication services to customers has
arisen. Many alternative distribution networks for digital data
have either already been developed or under development. For
example, in the near future, the digital data delivery services
just described that are delivered by the PSTN and CATV HFC
distribution facilities will also be competing with wireless local
loop delivery networks provided by Personal Communication Service
(PCS) companies and data delivery services under development by the
electric power utilities.
[0012] The problem is that the consumer has no way to know which
services will provide the most reliable, highest quality and least
expensive delivery mechanism for telephone and FAX service, e-mail,
distance learning, video conferencing, high speed world wide web
access, video on demand, remote LAN for telecommuters and
multimedia services. Further, over time, as each of the
subscription networks evolve and competitive pressures force
lowering of prices, it is possible that what was once the best
provider of, for example, video-on-demand (hereafter VOD), is no
longer the best provider but some other technology is. As another
example, ADSL does not have sufficient upstream bandwidth if video
telephony becomes a popular application whereas cable modems do.
However, variable bit-rate MPEG2 and advances in video compression
technology might save ADSL if video conferencing becomes big, and
High Speed ADSL may be adequate to service this application. The
problem this raises for consumers is that they do not want to
invest in technology for their home networks that only interfaces
to ADSL or cable modems and then be faced with the prospect of an
expensive replacement of their home network equipment in order to
interface their LAN with a new subscription service digital data
delivery network.
[0013] Another example involves supplying Plain Old Telephone
Service (POTS) to consumers via cable modem versus ADSL. Cutting of
a CATV line in the street or losing an above ground cable during a
windstorm will cut service to the entire neighborhood. That means
that everybody in the neighborhood who obtains their telephone
service via cable modem, will be left without phone service until
the break is repaired. In contrast, ADSL is a point-to-point
technology which causes only one customer to lose phone service if
her line is broken. A well maintained HFC CATV network may obviate
some of these problems, but that is unclear because there has not
been a great deal of field experience gained yet in POTS over
HFC.
[0014] Thus, a consumer will not know whether to buy a gateway that
can interface to an ADSL modem or an HDSL modem or a cable modem
until the bugs are worked out and competitive factors come into
play and make it clear which delivery network provides the best,
lowest cost service for this application.
[0015] However, one thing is clear: the above identified services
will be in demand, and the consumer would like to be able to take
advantage of the best delivery mechanism for each service and be
able to switch easily between delivery services as competition
forces adjustments in prices.
[0016] Since these services will arrive on many different media,
possibly in many different packet formats or using many different
protocols, a problem is created for the user in deciding what type
of home network data distribution system to buy and install. For
example, there may be different packet and cell sizes and different
header structures, different type of compression and different
protocols will be used. The user only wants to inexpensively and
conveniently distribute data encoding each of these services
throughout her premises to the various peripherals like digital
VCRs, DVD recorders/players, TVs, FAX machines, computers,
telephones etc. that need the data without having to have a
different gateway and local area network for each type of data
delivery service. Further, the user may want to use ADSL for some
services and cable modem for other services and wireless local
loops or satellite downlinks or some other data delivery network
option for other services.
[0017] A related problem is in the area of videoconferencing.
Currently, videophone offered by AT&T have been a commercial
failure because of the low picture quality of 2 frames per second
deliverable over standard twisted pairs. ISDN circuits can be used
for videoconferencing and ISDN videophones are available, and their
details are hereby incorporated by reference. However, the higher
cost of ISDN and its lesser availability to all homes has slowed
the acceptance of ISDN videoconferencing. Switched 56/64 Kbps
circuits can also be used for video conferencing by bonding or
grouping into multiple channels. Switched 384 Kbps connectivity can
also be provided on the basis of fractional DS1 or through ISDN PRI
channels in a channel group known as an HO. However, the cost and
availability issues that are slowing ISDN teleconferencing also
exist for switched 56/64 and switched 384 Kbps services as
well.
[0018] Likewise, DS-1 facilities support full-motion, high-quality
videoconferencing over dedicated networks at rates of up to 2.048
Mbps for E1 and 1.544 Mbps for T1. However, DS-1 facilities are
costly and not widely deployed and, although they are affordable
for large organizations with DS-1 backbones, they are out of reach
for the home network consumer.
[0019] Broadband networks such as ADSL, B-ISDN, HFC and cable
modems, satellite etc. are likely to be much more convenient and
affordable ways of delivering videoconferencing services via ATM
operating at DS-1 or DS-3 or higher speeds.
[0020] Thus, a need has arisen for a system which interface to many
different subscription service data delivery networks and can
distribute digital data throughout a customer premises in an
economical fashion to all the peripheral devices that need the data
using a uniform protocol and addressing scheme. Preferably, the
system will have an economical and reliable local area network on
the consumer premises side and have the flexibility to couple to
many different subscription service data delivery network media
types and translate from whatever packet/cell/frame type and
protocols are used by the data delivery network without substantial
expense to reconfigure or buy new equipment or software each time a
data delivery network option appears that is better, cheaper or
more reliable than the consumer's current service provider.
SUMMARY OF THE INVENTION
[0021] A home network system within the genus of the invention
would have a host bus and host computer programmed to do management
and control functions and a routing function, one or more local
area network interfaces and one or more external network
interfaces.
[0022] An important subgenus within the overal genus would be
characterized by a modular, expandable gateway construction which
interfaced any one of a number of external networks and
subscription services to peripheral devices in a customer premises
coupled to the gateway by one or more local area networks. Such a
modular gateway species would have as many shared components as
possible including a network interface to drive a local area
network that communicates digital data of various services and a
routing process and possibly an IP packetization process running on
the host computer. However, expandability would be provided by
interfacing the gateway to one or more external networks using
modular plug-in expansion circuits or modules to implement the
unique interfaces with various types of data delivery networks.
Some of the expansion modules are receivers capable of receiving
analog signals and digitizing and compressing them and supplying
the compressed data to said host computer. Others are receivers for
receiving and recovering video and other data in digital form which
has been modulated onto a dowstream carrier for transmission to
said customer premises and supplying the recovered digital data to
said host computer. Others of the expansion modules are
transceivers capable of receiving analog signals and digitizing and
compressing them and supplying the compressed data to said host
computer or receiving and recovering video and other data in
digital form which has been modulated onto a dowstream carrier for
transmission to said customer premises and supplying the recovered
digital data to said host computer. These transceivers include an
upstream transmitter for receiving digital data from said host
computer, preferably as an IP format packet, and transmitting it
outbound on an external network to a headend modem, a DSL central
office, a server connected to the internet at the locaton of an
internet service provider via a dialup connection or to a satellite
uplink facility via a dialup or direct connection.
[0023] For example, in a species using an Ethernet local area
network, the gateway would have a shared Ethernet Network Interface
Card (hereafter NIC) and an Ethernet protocol stack. This hardware
and sofware drives one or more 10BaseT, Fast Ethernet, or 100BaseT
local area networks coupled to the gateway that function to
distribute downstream data to various devices such as telephones,
computers, televisions, FAX machines etc. scattered throughout the
customer premises. The local area network(s) also collect upstream
data from the various peripherals spread throughout the consumer
premises and transfer this data to the gateway. Other shared
functions would include the power supply, bus structure and the
host processor and routing process, an IP packetization process,
possibly MPEG compression and decompression, possibly DES or other
encryption and decryption processes, MAC layer and/or IP address
resolution, and, possibly, IP telephony and/or PBX processes to
control IP telephony and/or PBX expansion modules. Some data
delivery networks use MPEG compression and others do not and some
services use encryption and others do not. Thus, depending upon the
external network and subscription or other service involved, the
expansion module that interfaces the gateway to the external
network may include whatever compression/decompression, address
resolution and encryption/decryption functions necessary to
successfully communicate with those data delivery networks.
[0024] Generally, the plug-in external network interface modules
that interface to each external network will include all those
circuits and software processes such as protocol stack peculiar to
communication with that particular external network and a
particular subscription service. These circuits can include any
necessary line coding and decoding, demodulation, detection,
demultiplexing, encoding, compression, access control and other
circuitry such as decryption and re-encryption circuitry necessary
for receiving data from or transmitting data to the particular
external network and subscription service the interface is designed
to work with.
[0025] One of the advantages of the modular structure is, for
example, if a consumer is getting their digital data delivery
services by ADSL using one particular ADSL modem line coding, and
another service provider with a different line coding provides a
better service which the consumer wants to take advantage of, the
consumer need only buy an ADSL interface board having the
appropriate line coding to switch services and does not need to buy
an entirely new gateway.
[0026] However, the modular construction is not an essential
element of the invention. For example, the teachings of the
invention also contemplate a subgenus of simple stand-alone,
nonexpandible gateways which only include one or more external
network interface circuits which are always present. These types of
gateways can be used by customers who know exactly which external
networks and subscription services they will use and who have no
need or desire to change. FIGS. 4A and 4B are supposed to symbolize
a species within this subgenus which happens to include external
network interfaces to an ADSL line, C-band and Ku band satellite
dishes, an HFC drop line and a terrestial TV antenna.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a diagram of a prior art connection between the
internet and a home local area network through a cable modem and
the HFC of a CATV system.
[0028] FIG. 2 is a diagram of a prior art connection between the
internet and a home local area network through an ADSL modem.
[0029] FIG. 3 is a diagram of a home network having a gateway
within the genus of the invention which couples any one of a number
of different subscriber service data delivery networks which are
external to a customer premises to one or more local area networks
that deliver digital data from said external networks to one or
more devices in said customer premises coupled to said local area
networks. The gateway does the necessary protocol conversions and
translations between the protocols and packet formats of the local
area network and the protocols and packet formats of the subscriber
service data delivery external networks.
[0030] FIGS. 4A and 4B are a detailed diagram of a gateway having
ADSL, satellite, cable and broadcast TV antenna interface
circuitry.
[0031] FIG. 5 is a block diagram of a video adapter for coupling a
local area network to a television.
[0032] FIGS. 6A-6E are a flowchart of a pull technology video on
demand process.
[0033] FIG. 7 is a flowchart of a wideband internet access
process.
[0034] FIG. 8 is a block diagram of a modular construction for the
gateway.
DETAILED DESCRIPTION OF THE PREFERRED AND ALTERNATIVE
EMBODIMENTS
[0035] FIG. 1 is a diagram of a prior art connection between the
internet and a home local area network through a cable modem and
the HFC of a CATV system. The internet is shown as cloud 11. An IP
router 13 in the headend facility 15 of an internet service
provider bidirectionally couples IP packets to the internet using
the TCP transport protocol. An optional local proxy server 17. The
proxy server is coupled to the IP router and provides local content
as well as caching certain very popular web pages such as Yahoo or
CNN news etc. so that they can be sent to cable modem subscribers
with greater speed. A control circuit 19 concentrates all IP
traffic from the subscribers coupled to the HFC network and sends
it to the IP router 13 and distributes packets from the IP router
to the various fiber optic links of which line 21 is typical. The
fiber optic links couple the headend to fiber nodes of which node
23 is typical. Each fiber node couples the fiber optic link to a
coaxial cable feeder branch of which branch 25 is typical. Each
feeder branch has at least one bidirectional amplifier, of which
amplifier 27 is typical. Each feeder branch is coupled to a
plurality of drop lines, of which drop 29 is typical, which couples
the branch to a cable modem at the subscriber premises. Cable modem
31 is typical and can be any of the cable modems identified below.
The cable modem has a 10Base-T output port which is coupled to an
Ethernet LAN 33 which runs throughout the home to peripherals such
as TV 39, telephone 37 and personal computer 35. A typical example
of cable modem 31 is the U.S. Robotics Cable Modem CMX. This modem
will work on any cable system that complies with the MCNS
data-over-cable specification. This cable modem comes with an
EtherLink network interface card and is compatible with the Windows
and Macintosh operating systems.
[0036] Referring to FIG. 2, there is shown a prior art connection
between the internet and a local area network in a home via the
telephone system using ADSL modems. The internet 11 is coupled to
IP router 13 via DS 1 (1.544 Mbps supporting 5 or more continuous
users or up to 55 users with 10% usage), DS 3 (45 Mbps supporting
up to 1500 subscribers) or OC-3 connections. Optional proxy server
17 serves the same function is served in the cable modem system of
FIG. 1. ADSL modems 41 and 43 at the subscriber premises 45 and
central office 47 couple to the twisted copper wire pair that was
originally used for POTS. A POTS splitter, not shown, forwards the
analog voice transparently to the POTS central office in a
frequency below the ADSL domain. The ADSL modem 41 connects
directly to the Ethernet port of a personal computer or to an
Ethernet hub. The access switch 53 serves to concentrate access
lines from the ADSL modems such as 43 into router ports of IP
router 13. Access adapter 53 is likely to include ATM switch
fabric. The ADSL modem 41 can be the 3Com HomeConnect ADSL Modem
Ethernet or any equivalent ADSL modem.
[0037] Referring to FIG. 3, there is shown a diagram of a home
network having a gateway within the genus of the invention which
couples any one of a number of different subscriber service data
delivery networks which are external to a customer premises to one
or more local area networks that deliver digital data from said
external networks to one or more devices in said customer premises
coupled to said local area networks. The gateway does the necessary
protocol conversions and translations between the protocols and
packet formats of the local area network and the protocols and
packet formats of the subscriber service data delivery external
networks. The home network is useful for distribution of digital
data that encodes video on demand, distance learning, video
conferencing, telephone service, internet web pages and FTP
download files, e-mail and other digital subscriber services to
multipled devices over one or more local area network that runs
throughout a customer premises. Digital data or analog signals
implementing the subscriber service (subscriber service is used
loosely to mean all signals whether analog or digital transmitted
to the customer premises via an external network of any type
including a TV antenna) is transmitted to the customer premises.
Gateway 14 converts the incoming signals to digital data in
Ethernet packets and transmits it to the requesting device coupled
to the local area network.
[0038] The gateway 14 functions to do all the physical layer
interfacing and protocol conversions necessary to couple one or
more local area networks that run through the customer premises to
digital data distribution services delivered via the Hybrid Fiber
Coax (HFC) of a cable television system, or a digital satellite
data distribution network or the phone lines of the public service
telephone network. Hereafter, these digital data delivery networks
external to the customer premises will be called the subscription
networks or the digital data delivery networks even though some or
all of them may also deliver analog signals as well as digital
data. For example, the cable TV subscription network 16 will
deliver analog CATV signals in addition to the digital data carried
on its upstream and downstream carriers. Likewise, the satellite
dish 56 will deliver broadcast TV signals as well as digital data
modulated on the downstream carrier. The Public Service Telephone
Network (PSTN) telephone lines 58 will also deliver analog
telephone signals in addition to digital data modulated onto the
upstream and downstream carriers of the ADSL service.
[0039] The gateway 14 is typically a Pentium or Celeron class
personal computer host with protocol conversion and switching
control programs that cooperate with the operating system to
control the operations of various interface circuits and having one
or more network interface circuits that drive the media of the
local area network(s). In some embodiments, the interface circuits
can be built on the motherboard with the host microprocessor.
However, in the preferred embodiment, each interface circuit is a
separate expansion card that plugs into the system bus of the host
and has a connector suitable to interface with the physical media
of the particular digital data delivery service. Likewise, the
network interface to the local area network(s) can be an expansion
card. However, it is preferable for the local area network
interface circuit to be built into the motherboard so as to not
consume an expansion slot. In this modular type construction, the
circuits and software that are common to all the expansion modules
that interface to the various subscription networks are shared by
the expansion module interface circuits. Thus, the host
microprocessor, hard disk, RAM, CD-ROM/DVD, power supply, network
interface circuits for the LAN(s), display and keyboard are all
shared as are the operating system, management sofware and any
protocol conversion software layers that are common to all network
interface circuits. Likewise, the gateway 14 is going to have a
packet switching process and a crossbar switch or other switching
circuitry controlled by the switching process to route packets
received from the subscription providers to the appropriate LAN and
vice versa based upon the IP or other addresses in the headers of
the packets. These two elements can also be shared by the expansion
module interface cards as the switching services need to be shared
by all the subscription network interface cards in the gateway. The
circuits and software that are specific to any particular
subscription network such as MPEG compression or decompression,
tuning, detection and demodulation, carrier and clock recovery,
video decoding, A/D or D/A conversions etc. are located on the
expansion module interface card dedicated to that subscription
network.
[0040] This preferred modular construction has two significant
advantages. First, it protects the subscriber's investment in the
gateway by providing flexibility to couple the gateway to any
subscriber network that turns out to be the most reliable, least
expensive, most flexible or easiest to use or least aggravating
subscriber network for supplying any particular digital data based
service desired by the user. For example, if ADSL turns out to be
the best provider of telephone and video telephony services, but
HFC turns out to be the best provider of video on demand or
distance learning services, and these are the only services the
user is interested in purchasing, the user can simply buy expansion
modules to interface with these two subscription services. There is
no need to invest in a gateway that has hardware and software to
provide high speed internet access as well as these other services
since the user is not interested in purchasing high speed internet
access. This first advantage also extends to the situation where
the user later changes her mind and decides that high speed
internet access is useful, but determines that satellite delivery
by DirectPC.TM. is the best way of obtaining this service. In such
a case, the user does not have to buy an entirely new gateway, but
can simply buy an additional modular expansion card for interfacing
to a satellite dish.
[0041] The second advantage of the modular construction of the
gateway is the property it has of protecting the subscriber's
investment in the gateway by decoupling the physical structure and
software of the shared components of the gateway from changes in
the particular subscription networks. As these subscription
networks evolve, there are likely to be changes in the protocols,
physical media, packet structure etc. which are unpredictable in
nature. Further, it may evolve over time with competitive forces
similar to those acting on the long distance carriers that
competition alters the picture as to which subscription network is
the best provider of each particular service in which the
subscriber is interested. If ADSL no longer is the best provider of
telephony services, and the HFC networks offer a better deal, the
consumer does not have to buy an entirely new gateway, but can
simply remove the ADSL interface card and substitute a cable modem
card to interface with the HFC network if a cable modem card is not
already present. Likewise, if ADSL with Carrierless Amplitude/Phase
modulation (CAP) give way to Discrete Multitone (DMT) modulation as
the new standard, the user can simply swap out the CAP based ADSL
expansion module for a DMT based module.
[0042] The structure of one embodiment of the gateway 14 will be
discussed in more detail later. However, the genus of gateways 14
which are within the teachings of the invention is defined by the
following characteristics which all will share:
[0043] a programmed host computer with an operating system, and one
or more protocol conversion processes and a switching control
process that controls a packet switch to route packets between the
one or more subscription service networks and the local area
network(s) to which the gateway is coupled;
[0044] one or more interface circuit for the particular local area
network(s) coupled to the packet switch to drive packets out onto
the physical media of the LAN(s);
[0045] either a single interface circuit that can interface to all
of HFC, PSTN and satellite digital data delivery networks which is
either on the motherboard of the host or separate from the
motherboard and coupled to the host system bus, or a plurality of
expansion slots for coupling individual subscription network
interface modules to the host system bus as desired so that each
module can share the common facilities of the host needed to
support the module; and
[0046] wherein the common elements of the host that can be shared
by all the subscription network interface circuits for all the
subscription networks to which the gateway is coupled are shared,
with examples of such shared circuits being: the host
microprocessor, hard disk, RAM, CD-ROM/DVD, power supply, network
interface circuits for the LAN(s), display and keyboard, the
operating system, any management sofware and any protocol
conversion software layers that are common to
[0047] all network interface circuits and a packet switching
process and a crossbar switch or other switching circuitry.
[0048] The gateway 14 will have a cable modem circuit either on a
modular expansion card or as part of the subscription network
interface circuits board. This cable modem circuitry can be any of
the cable modems that are known in the prior art which are
identified herein or any new cable modem design that surfaces after
this application is filed since the details of the cable modem are
not believed at the present time to be critical to the
invention.
[0049] Likewise, the gateway 14 will have as part of its interface
circuit board or as an expansion card module, an ADSL modem (or
SDSL or HDSL modem) to receive incoming digital data modulated onto
a downstream carrier and output it as Ethernet packets on LAN(s) 18
and 20. In some alternative embodiments, LANs 18 and 20 could be
ATM LANs or one could be ATM and the other Ethernet or some other
technology such as Fibre Channel Arbitrated Loop with suitable
adjustments in the gateway 14 to packetize the data properly and
use appropriate circuitry and protocols at all levels from the
physical layer, MAC and network or routing layers up to the
application layer for the particular LANs in use. ATM LAN switches
and routers are available in the prior art and the details of their
construction are hereby incorporated by reference.
[0050] Likewise, the ADSL modem receives Ethernet packets with
digital data encoding voice, pictures, video etc. and modulates
that data onto an upstream carrier. ADSL carves up the local loop
bandwidth (the bandwidth of the twisted pair telephone line from
the consumer premises to the Central Office) into several
independent frequency channels suitable for any combination of
services inclduign voice, ISDN, VOD programming and interactive
gaming. Downstream data rates vary from 1.544 to 6.144 Mbps with
upstream rates from 16 to 640 Kbps. The gateway ADSL interface
circuit will also have a voice splitter if regular analog telephone
are to be supported in addition to the LAN-connected video phones
60 and 62 or other data-consuming phones or FAX machines like FAX
64 which receive and transmit voice and pictures or caller ID or
other data in digital form. Such other data can include such things
a background information file on the person identified by caller ID
data transmitted by an application on the PC 22 which supports the
phones. Any conventional ADSL (or SDSL or HDSL) modem design such
as the known ADSL modem manufactured by 3COM (specifically
identified below and incorporated by reference herein) may be used
for the PSTN ADSL interface circuitry or the ADSL expansion module
as the details of the ADSL interface circuitry are not believed to
be critical to the invention. The 3COM ADSL modem couples to a
twisted pair carrying ADSL services and has an Ethernet 10Base-T
output for coupling to the LAN(s) 18 or 20 through the shared
packet switching circuitry of the gateway.
[0051] The gateway 14 also includes as part of its subscription
network interface circuit board or as part of its satellite network
expansion module a decoder box. This satellite decoder box is of
known design suitable to receive, demodulate, demultiplex, detect
and decompress (if necessary) digital data transmitted on a
downlink to satellite dish 56. This digital data may be transmitted
via a service such as DirectPC or other satellite-based, digital
data delivery services which may become available in the future,
and the interface circuitry necessary to receive digital data
transmitted to a particular PC via satellite is known in the
DirectPC application, and is hereby incorporated by reference.
Typically, such satellite interface circuitry includes a tuner, a
QPSK demodulator, a transport demultiplexer and a conditional
access circuit. If the satellite interface circuit is being used to
receive digital video signals that are compressed, the satellite
circuitry may include circuits to decompress the digitized video
back to its original state (or close to its original state if lossy
compression such as MPEG is used). However, since uncompressed
broadcast quality standard NTSC video requires a bit rate of
slightly over 221 Mbps, whether the satellite interface circuitry
of the gateway includes decompression circuits depends upon the
bandwidth of the local area network(s) coupled to the gateway. If
the LAN(s) are 10Base-T or 100Base-T, the video digital data will
be left compressed and can be transferred over the LAN(s) with
quite acceptable quality at T1 speeds of 1.544 Mbps. MPEG
compression and decompression is known in the art and is
incorporated by reference herein. MPEG compression is lossy
compression which uses: a 7-tap filter for averaging 7 neighboring
pixels or lines; color space conversion; scaling to the
presentation resolution before digitization; transforms such as the
Discrete Cosine Transform, vector quantization, fractal transform
and wavelet compression; and quantization or compaction encoding to
reduce the number of bits needed to represent a color pixel such as
run-length encoding, Huffman coding, and arithmetic coding; and
interframe compression to transmit only the pixels that change
between frames. Many compression standards exist such as Px64,
JPEG, MPEG 1 and 2 (MPEG 2 with transmission rates of 4 to 100 Mbps
is already in use for digital video transmission via satellite
services such as DirecTV) and MPEG 4 (a low bit rate standard
intended for videophones and other small screen devices). The
compression and decompression circuitry for all these standards is
hereby incorporated by reference.
[0052] Further, the satellite interface circuitry or satellite
expansion module should also include a convention telephone modem
for making dial up access to the internet via the PSTN for upstream
data transmissions through the server of the internet service
provider. Downloads from the internet or a video server or some
other digital service server are beamed up to the satellite and
retransmitted on the downlink addressed to the specific user that
requested the downlink. All other decoder boxes coupled to
satellite dishes that received the same broadcast reject the
packets so received as not addressed to them.
[0053] In the embodiment shown in FIG. 3, a cable modem 12 is shown
externally to the gateway with the output IP or Ethernet packets
encapsulating IP packets or ATM cells on bus 16 for coupling into
the packet switching process inside the gateway. The preferred
embodiment however is as shown in FIGS. 4A and 4B with the cable
modem circuitry inside the gateway as shown at 70. The particular
cable modem shown at 70 is labelled as DOCSIS 1.2 compatible, but
it can be any known cable modem design as can the external cable
modem.
[0054] Referring to FIGS. 4A and 4B, we turn now to more specific
information about each of the possible subscription services
digital data delivery networks and the interface circuitry in the
gateway 14 needed to couple each said external network to the LAN
at the customer site. The gateway 14 can be a standalone circuit
with all the interface circuits needed to interface to one or more
external networks included as a permanent part thereof with no
plug-in expansion capability as opposed to the preferred modular
construction shown in FIG. 8 where external network interface
circuits may be added as needed.
[0055] First, digital data services may be delivered by a coaxial
cable 10 which represents the drop line in a cable TV HFC network
(not shown). The cable TV network has a head end modem (not shown)
which couples the HFC cable CATV plant to wide area networks such
as the internet as well as the public service telephone network
(hereafter PSTN) through one or more routers, bridges or gateways
(not shown). The head end modem may also couple the HFC to local
servers such as VOD servers.
[0056] Digital data encoding video signals, telephone service, data
being received from the internet etc. is modulated by the head end
cable modem onto one or more downstream channels for simultaneous
transmission on the HFC cable plant with regular analog cable TV
programming. The cable TV channels each have their own frequency so
as to not conflict with each other. The downstream digital services
data is modulated onto a carrier that has a frequency that does not
conflict with the frequencies of the cable TV programming nor with
upstream data which is modulated onto a different upstream carrier
frequency. Data from different sources is multiplexed on both the
downstream and upstream channels by any known means including time
division multiplexing, code division multiplexing, synchronous code
division multiplexing or frequency division multiplexing.
[0057] Digital data can be delivered over the HFC using
Asynchronous Transfer Mode (ATM) or ATM over B-ISDN type services
adapted for HFC and the particular type of transmitters, modulation
and multiplexing being used. ATM and B-ISDN (Broadband ISDN) are
inexorably linked, and there are a plurality of standards set by
ITU-T that are in existence which are incorporated by reference
herein. Those standards are: 1.113; 1.121; 1.150; 1.211; 1.311;
1.321; 1.327; 1.361; 1.362; 1.363; 1.413; 1.432; 1.555; and 1.610.
ATM Forum Implementation Documents of significance that are
incorporated by reference herein are: ATM User-Network Interface
(UNI) Specification for PVCs; ATM Broadband Intercarrier Interface
(B-UNI) Specification and ATM Date Exchange Interface (DXI)
Specification; Internet Engineering Task Force Requests for Comment
(RFC) that are incorporated by reference are: RFC 1483: Definition
of Multiprotocol Encapsulation over AAL5; and RFC 1577: Definition
of Internet IP over ATM.
[0058] ATM is the delivery mechanism of choice since its small
48-octet payload and 5-octet header in each cell lends itself well
to video, image, facsimile, voice or data. Further, the fixed cell
size gives routers and switches the advantage of predictability, as
compared to a variable length frame. These two considerations yield
decreased delay as data moves through the switching system and
across the transmission links in frequent little blasts. No long
frames need to be transmitted tying up switch ports and thereby
causing delays for frames from other sources that need to use the
same ports. ATM also has the advantage of being able to adjust the
amount of bandwidth required to support a session during the
session. However, ATM networks do not provide either error
detection and correction or protocol conversions. Those functions
are left up to the user.
[0059] Likewise, digital data may be delivered over HFC using
Discrete Multi Tone (DMT) technology typically used in ADSL but
adapted to HFC and the particular type of transmitters, modulation,
multiplexing being used. DMT is a new technology developed for ADSL
delivered via twisted pairs that uses DSPs to pump more than 6 Mbps
of video, data, image and voice signals over todays existing one
pair copper wiring, but it could also be used to transmit data over
HFC cable plants. DMT provide 4 asymmetric "A" channels at 1.5 Mbps
each of which can provide an VCR quality signal and which can be
ganged together such that two A channels can deliver a "sports"
quality video channel and all four A channels operating together
can deliver digital Extended Definition TV signals. DMT also
delivers one "H zero" channel at 384 Kbps to deliver Northern
Telecomm's multirate ISDN Dialable Wideband service or equivalent.
This channel can also be used for work-at-home telecommuters for
high bandwidth access to the corporate LAN using Northern
Telecomm's DataSPAN or other frame relay services. DMT also
delivers one ISDN Basic Rate channel containing two "B" channels at
64 Kbps and one "D" channel at 16 Kbps. The Basic Rate channels
allow access to a wide range of emerging ISDN services without
requiring a dedicated copper pair or the expense of a dedicated NT1
unit at home. These channels also permits the extension of Northern
Telecom's VISIT personal video teleconferencing services to the
home at fractional T-1 rates (P.times.64). DMT also delivers one
signalling and control channel operating at 16 Kbps giving the home
user VCR type control over VOD movies and other services including
fast-forward, reverse, search and pause functions. Finally, DMT
also delivers embedded operations or overhead channels for
administration, internal system maintenance, audits etc. All this
is delivered without interrupting the POTS service if it is
delivered over a copper pair. HFC could also potentially deliver
POTS, but without a dedicated pair to each home, such service would
be subject to congestion and loss of POTS to entire neighborhoods
served by a single cable in case of a failure of the cable.
[0060] In the embodiment shown in FIG. 3, digital data on the HFC
drop line is recovered by any known cable modem 12. One example of
a suitable cable modem using SCDMA upstream multiplexing is given
in PCT publication WO 97/08861, published 6 Mar. 1887, which is
hereby incorporated by reference. One example of software and
hardware in the cable modem 12 which is Docsis 1.2 compatible is
given in the following U.S. patent applications, all of which are
hereby incorporated by reference: Ser. No. 09/074,036, filed May 6,
1998 entitled APPARATUS AND METHOD FOR SYNCHRONIZING AN SCDMA
UPSTREAM OR ANY OTHER TYPE UPSTREAM TO AN MCNS DOWNSTREAM OR ANY
OTHER TYPE DOWNSTREAM WITH A DIFFERENT CLOCK RATE THAN THE
UPSTREAM; Ser. No. 09/152,645, filed Sep. 14, 1998, entitled METHOD
AND APPARATUS OF USING A BANK OF FILTERS FOR EXCISION OF NARROW
BAND INTERFERENCE SIGNAL FROM CDMA SIGNAL; Ser. No. 09/152,643,
filed Sep. 14, 1998, entitled TWO DIMENSIONAL INTERLEAVE PROCESS
FOR CDMA TRANSMISSIONS OF ONE DIMENSIONAL TIMESLOT DATA; Ser. No.
09/337,167, filed Sep. 21, 1999, entitled MIXED DOCSIS 1.0 TDMA
BURSTS WITH SCDMA TRANSMISSION ON THE SAME FREQUENCY CHANNEL; Ser.
No. 08/760,412, filed Dec. 14, 1996, entitled LOWER OVERHEAD METHOD
FOR DATA TRANSMISSION USING ATM AND SCDMA OVER HYBRID FIBER COAX
CABLE PLANT published as PCT publication WO 97/34421 on 18 Sep.
1997. The PCT publication WO 97/34421 published on 18 Sep. 1997
explains hardware and software for transmitting IP packets received
from the internet over HFC using ATM cells and virtual channels to
a remote unit cable modem and distributing the data to peripherals
via a local area network. Specifically, WO 97/34421 teaches:
[0061] receiving Internet Protocol packets directed to an entity
having an IP address out on a LAN at a customer premises and
looking up Ethernet source and destination addresses mapped to that
IP address and generating an Ethernet header and appending it to
the IP packet;
[0062] adding RFC 1483 bits and CRC bits and sufficient pad bits to
make up an integer number of ATM cell payload section of 48 bytes
to result in an AAL5 format packet;
[0063] parsing the resulting AAL5 packet into a plurality of ATM
cell payload sections of 48 bytes each;
[0064] adding a standard 5 byte ATM cell header to each ATM
cell;
[0065] encoding the PTI field of the ATM cell header with a bit
which signals which cell is the last cell in the packet;
[0066] outputting the ATM cells to a formatter circuit in the head
end cable modem as an OC3 TDMA stream;
[0067] optimizing ATM cell headers to reduce the size of the
headers down to two bytes comprising the 16 least significant bits
of the VPI/VCI field and encoding the last cell data into two 9th
bits of the two 9-bit sections of the downstream optimized ATM cell
header;
[0068] encoding the 9th bits of each of the first eight "bytes"
(byte here is used in the sense of a 9-bit entity); parsing the
optimized ATM downstream cells into 9-bit bytes and sending them as
a TDM stream to the headend cable modem downstream transmitter for
transmission (this transmitter can be any conventional transmitter
but preferably is an SCDMA transmitter which divides each 9-bit
byte into three tribits and interleaves them into elements of an
information vector that correspond to virtual channels assigned to
the particular modem to which each 9-bit byte is directed, and
spreading the spectrum of the information vector using one or more
spreading codes assigned to the one or more assigned virtual
channels);
[0069] headend cable modem transmitter encodes the 9-bit bytes and
modulates them onto a downstream carrier for transmission over
virtual channels from a head end over HFC to a remote unit (RU)
cable modem.
[0070] The optimized system uses a two level addressing scheme and
a mapping between each logical channel and the assigned RU for that
channel. The two byte header in the downstream optimized ATM cell
identifies the single logical channel upon which the data is to be
transmitted, and this single logical channel corresponds to a
single one of the multiple RUs. The Ethernet address of the
particular process or peripheral at the RU to which the payload
data is to be directed once it arrives at the RU is included as
several bytes in the payload data.
[0071] At the RU cable modem (12 in FIG. 3 or 70 in FIG. 4A), the
9-bit bytes are recovered, reassembled into AAL5 packets and
encapsulated into one or more Ethernet packets for transmission
over the LAN. Specifically, the RU cable modem carries out the
following processing:
[0072] the incoming signals from the cable drop 10 are demodulated,
demultiplexed and detected in accordance with whatever multiplexing
and modulation schemes that were used by the headend downstream
transmitter for the transmission on separate logical channels so as
to recover the 9-bit bytes;
[0073] a formatter circuit finds the ATM cell boundaries by
examining the 9th bits for the start code and reassembles the
50-byte optimized downstream ATM cell;
[0074] the formatter in each RU examines the 2-byte header in each
ATM cell to determine if the ATM cell is directed to that RU and
discards the cell if it is directed to another RU (RU and cable
modem at the customer premises) are used interchangeably herein)
and forwards it to a segmentation and reassembly circuit (SAR) as a
Utopia data stream if the cell is directed to this RU;
[0075] the SAR recovers the AAL5 packet boundaries by finding the
RFC 1483 bits and the last cell code and reassembles the AAL5
packet and error checks it using CRC bits and stores the corrected
AAL5 packet in memory for retrieval by an Ethernet controller and
passes a pointer to the packet to the Ethernet controller;
[0076] the Ethernet controller retrieves the AAL5 packet pointed by
each pointer and strips off the RFC 1483 bits and sends the
remaining bits as an Ethernet packet (after stripping the RFC 1483
bits, the remainder is an Ethernet header followed by an IP header
followed by a payload section).
[0077] In the embodiment of FIG. 3, if the cable modem 12 has the
structure and functionality just described, gateway 14 receives the
downstream Ethernet packet on line 16 and simply couples them
through a packet switching process on the gateway onto the
appropriate LAN subnet (if more than one LAN is used in the
customer premises). If only one LAN is used, the Ethernet packets
can simply be delivered to an Ethernet Network Interface Card in
the gateway for driving out onto the LAN. Likewise, Ethernet
packets received from the LAN having IP addresses indicating they
are directed to processes coupled to the wide area networks to
which cable modem 12 is coupled are routed through the gateway to
the cable modem 12. There, they are transmitted on an upstream
channel assigned to cable modem 12 and recovered by the head end
modem and coupled to the internet through a router at the head
end.
[0078] Other examples of high speed cable modems which could be
used for cable modem 12 are given in Azzam, High Speed Cable
Modems, (McGraw Hill 1997), ISBN 0-07-006417-2, which is hereby
incorporated by reference.
[0079] Typically, the local area networks 18 and 20 are 10Base-T
phone lines or Cat 3, 4 or 5 UTP (twisted pair) type LANs with any
topology. These LANs are inexpensive and there many sources of
inexpensive network adapters, hubs and peripherals. The physical
media of the LAN(s) 18 and 20 can be provisioned as a twisted pair
phone line with which the customer premises is already wired or it
can be CAT 5 wiring, or an RF or infrared wireless LAN system, or
the coax of the cable TV system that runs through the house can be
used for a ThickNet (10Base-5) or ThinNet (10Base-2) LAN. The
latter case assumes the coax has been disconnected from the
standard CATV drop line feed and is coupled to TV set peripherals
only indirectly through the cable modem 12. However, it is also
possible to maintain the connection of coaxial cable running
throughout the premises to the HFC cable drop 10 for delivery of
FDMA analog CATV programming channels to various TVs and VCRs in
the house and use the 10Base-T or wireless LAN for delivery of
digital services to the various peripherals through network adapter
circuits.
[0080] FIG. 3 shows gateway 14 as coupled to two LANs 18 and 20 one
of which is high speed and the other of which is low speed The high
speed LAN may be 100BaseT and is used to deliver high bandwidth
consuming services such as video conferencing, video on demand,
high speed internet access. There may be one or more LANs coupled
to the gateway. If there is more than one LAN, the gateway 14 also
provides a routing function to get the Ethernet packets onto the
appropriate LAN to which the peripheral having the IP address in
the packet is coupled.
[0081] The local area networks 18 and 20 also serve the dual
purpose of allowing the computers on the network to communicate
with each other and share resources such as shared hard disks,
printers etc. For example, PC 22, which is typically a Windows
based personal computer but which may also be a Macintosh or other
workstation, can communicate with network computers 24 and 26 to
allow files created on the hard disk of PC 22 to be accessed by the
network computers or to have documents created on the network
computers 24 and 26 stored on the hard disk of PC 22. Through the
gateway 14 and an internal ADSL modem or the cable modem, the
network computers can also access the internet and download web
pages, send e-mail etc.
[0082] Television set 28 is coupled to the local area network 18
via a network adapter 30 which functions to convert the compressed
digital data in received Ethernet packets to video signals on line
32. The TV may be used in interactive communications so upstream
data can be sent through the use of an infrared or RF wireless
keyboard 34. Such data might include the title or number of a VOD
movie to be ordered or upstream text to be sent in a multimedia
interactive presentation. In addition, an infrared or RF remote
control 80 can be used to transmit commands to the network adapter
30 such as play, pause, slow motion, stop, rewind etc. to control
video on demand services. Information the consumer wishes to send
is entered on the keyboard and communicated to the network adapter
30 via infrared or RF transmission from the keyboard 34 and/or
remote control 80. The data transmissions are received, demodulated
and detected to recover the data and the data is addressed and
packetized into IP packets encapsulated inside Ethernet packets by
an infrared and/or RF receiver 82 in the network adapter 30 (see
FIG. 5 which is a block diagram of the network adapter 30). The
Ethernet packets containing the upstream VOD request data are
addressed to the gateway 14. These packets are launched onto the
LAN 20 by a network interface card 84 which does the media access
control and physical layer protocols of whatever LAN is in use such
as CSMA/CD in the case of Ethernet LANs.
[0083] The IP packet encapsulating each VOD request is addressed to
the particular video server which will supply the data. Standard
mouse or touchpad type technology in the infrared keyboard and/or
remote control 80 sends pointer information to receiver 82 so that
the user can request menus from each video server and point to a
video selection from each menu displayed on the TV. In one
embodiment, the remote control 80 or IR keyboard 34 has function
keys that may be pushed to request menus of VOD selections from the
satellite, HFC and ADSL video servers. When these function keys are
pressed, the receiver 82 converts the request into an IP packet
addressed to the appropriate video server requesting transmission
of the current menu data. The menu data listing currently available
selections is sent as downstream IP packets addressed to the video
adapter having the IP address that was the source address of the
menu request packet. These IP packets reach the IP video circuit
242 where they are recognized and routed via bus 87 to the 2/3D
Graphics circuit 83 which converts the data into graphics data
signals on line 85 which will be used to display the menus.
[0084] When the user points to a particular menu selection on a
displayed menu, this pointing information is transmitted to the
receiver 82 and converted to graphics commands which are
transmitted via line 81 to optional 2/3D graphics circuit 83. The
graphics circuit 83 creates graphics for overlay on the TV display,
and the pointer information is converted to a graphics image such
as a pointer or hand which the user can move on the displayed menu
by use of a mouse or touchpad. When the user points to a VOD
selection and gives an "order" command, the menu in which the
pointer lies is transmitted via bus 81 to the receiver 82 and the
position on that menu where the pointer currently is located is
determined by graphics circuit 83 and transmitted to the receiver
82. The menu and current position data so determined are mapped to
an IP address of a particular server and a particular VOD selection
available from that server. The receiver 82 then uses the IP
address of the video server as a destination address and its own IP
address as a source address and the requested selection to create
an IP packet bearing the VOD request. This packet is then
encapsulated into an Ethernet packet addressed to gateway 14 and
sent to the gateway via the NIC 84 and the LAN 20. The gateway
strips off the Ethernet header and routes the IP packet to the
appropriate video server via the appropriate upstream media for
that video server.
[0085] In alternative embodiments, the user may simply type in the
number of a category of video from a displayed menu of available
categories and the number of a video selection on the displayed
menu. The menu number and program number are then converted into a
VOD request IP packet by the receiver 82 and then encapsulated into
an Ethernet packet addressed to the gateway 14. The gateway 14 then
processes the VOD request as described above.
[0086] When the upstream VOD request packet reaches the gateway 14,
it is processed by the Ethernet (or other LAN protocol) to IP
protocol conversion and routing process (hereafter referred to as
the routing circuit) carried out by the host computer circuitry and
the software processes symbolized by block 86 in FIG. 4A (FIGS.
4A-4B together are a block diagram of one embodiment of the
gateway). The routing circuit 86 then routes the VOD request packet
to the appropriate subscription service data delivery network for
delivery to the process/target device named in the IP destination
address.
[0087] The routing circuit 86 is shown as a separate logical block
in FIG. 4A from the host microprocessor 128 and its associated
peripherals: random access memory 129, nonvolatile memory 131 to
store the bios, hard disk controller 133 and the hard disk 135 it
controls, display adapter 137 and display 139, keyboard interface
141 and keyboard 143. All of these peripheral devices are
conventional. In an actual circuit, the routing circuit 86 is
usually the host microprocessor programmed to do the IP to Ethernet
and vice versa protocol conversions, routing table construction and
packet routing functions along with any other functions necessary
for a router including network interfaces and any other functions
required of the routing process described in the flowcharts herein.
Descriptions of gateways, routers, the Internet Protocol and IEEE
802.3 Ethernet local area networks are found in Tanenbaum, Computer
Networks, 2nd Ed. (Prentice Hall 1989) ISBN 0-13-162959-X, and
Stallings, Data and Computer Communications, 4th Ed., (MacMillan
Publishing 1994) ISBN 0-02-415441-5, which are both hereby
incorporated by reference.
[0088] The function of the gateway is to provide protocol
conversion, packet format conversion, video, voice and data
demodulation, detection and demultiplexing services, conditional
access control to prevent non subscribers from receiving services
they have not subscribed to. The gateway 14 performs the functions
of a cable modem and a set-top decoder box for a satellite digital
data subscription service such as DirectPC and performs the
functions of an ADSL modem. As part of this interface circuitry,
the gateway performs MPEG encoding services, IP video. IP video
comprises the process of recovering downstream IP packets and
sending them to an input port of a routing process and receiving
Ethernet upstream packets and converting them to IP packets and
sending them upstream. The gateway also performs IP telephony
services (similar to the IP video services except for telephony
over the internet) as well as switching and routing services. More
details about the structure and operation of the gateway will be
included below.
[0089] It is up to the network interface cards of the peripherals
to receive the Ethernet packets from LAN 18, determine if they are
directed to the Ethernet address of that peripheral, convert the
payload data to a format useable by the peripheral, and to transfer
the data to the process having the IP address in the packet.
[0090] Assuming that the service being carried by the home network
requires bidirectional data transfer and ATM is to be used
upstream, the upstream data transmission process from the
peripheral to the internet via the cable modem 12 is as follows
assuming the cable modem is of the type defined in PCT publication
WO 97/34421 which is incorporated by reference herein:
[0091] the application process that needs to send upstream data
outputs one or more Ethernet packets onto the LAN 18 which include
the IP address of the entity on the internet to which the data is
directed;
[0092] each Ethernet packet gets routed through the gateway 14 to
the cable modem 12 if it has an IP address which indicates it is
directed to an entity on the internet to which the gateway is
coupled through the cable modem 12;
[0093] the SAR in the RU cable modem adds pad bits to each Ethernet
packet, computes CRC-32 error detection bits, and adds RFC 1483
bits such that the resulting packet is an integer multiple of 48
bytes;
[0094] the SAR parses the packet into multiple 48-byte ATM cell
payload sections with no header bytes, adds standard 5-byte ATM
cell headers to each payload section using a virtual link
identifier which identifies the virtual upstream channel assigned
to that RU to construct the VPINCI fields and using last cell,
normal cell and idle cell information to construct the PTI field
and calculates a HEC field and transmits the resulting ATM cells to
a formatter as a Utopia stream;
[0095] the formatter adds a 9th bit to each byte in the cell and
encodes the 9th bits with a start code, last cell, normal cell and
idle cell codes using the information in the PTI field of each ATM
cell header;
[0096] the formatter strips off the 5-byte header of each ATM cell
while saving the information and then parses each upstream ATM cell
into 9-bit bytes and places one 9-bit byte into each timeslot of an
upstream information vector which corresponds to the virtual
channel assigned to this RU modem and transmits the information
vector to the upstream transmitter in the RU cable modem 12 using
the information in the VPI/VCI field of the header to identify
which virtual channel in which each 9-bit byte from each ATM cell
is to be transmitted;
[0097] the upstream transmitter of the RU modem transmits the
upstream data in the appropriate virtual channel such as by
spreading the spectrum of the 9-bit bytes using one or more
spreading codes assigned to the virtual channel(s) assigned to the
RU;
[0098] the spread spectrum data is then transmitted on the upstream
carrier;
[0099] the receiver in the headend cable modem receives the
upstream transmissions from each RU and demodulates, demultiplexes
and detects the transmitted data of each 9-bit byte and places the
recovered 9-bit bytes into the timeslots on a TDMA bus which
correspond to the logical channel in which the data was
received;
[0100] a formatter process in the headend modem demultiplexes the
TDMA stream and reassembles the 48-byte optimized upstream ATM
cells using the signalling data in the 9th bits and places each ATM
cell in a portion of a cell buffer dedicated to storing ATM cells
from the RU which generated the data using the timeslot data to
determine from which RU each ATM cell arrived;
[0101] a cell output controller process then retrieves each 48-byte
ATM cell and generates a standard 5-byte header and transmits the
standard 53-byte ATM cell in an OC3 format data stream to a
segmentation and reassembly circuit in a router in the headend
cable modem;
[0102] the SAR error checks the 53-byte ATM cell using the HEC
field and strips off the header bytes while retaining the VPI/VCI
and the PTI field information and reconstructs the AAL5 sequence
using RFC 1483 bits and the last cell data encoded in the PTI field
to find the packet boundaries and by concatenating 48-byte payload
sections of the ATM cells and error checks the packet using CRC
bits;
[0103] if no errors are found, the RFC 1483 bits and the CRC bits
and pad bits are stripped off to leave an Ethernet packet header,
an IP header and a payload section and the result is sent to a
router for routing on the appropriate subnet to get to the
destination having the IP address somewhere out on the wide area
network.
[0104] If the cable modem 12 has the architecture of any of the
cable modems described in Azzam, High Speed Cable Modems, suitable
modifications to the above described downstream and upstream
processes described above can be made, or the upstream and
downstream processes used in those modems can be used for delivery
of the same digital services they have used in the prior art to
deliver. For example, any of the cable modem hardware and software
structures known in the prior art which have been used in the
actual field trials identified in Azzam, High Speed Cable Modems,
Chapter 14, Section 14.2, pp. 512-518 (McGraw Hill 1997), ISBN
0-07-006417-2, may be used, and all of these modem designs are
hereby incorporated by reference. The cable modems whose circuitry
and software is incorporated by reference herein include: the
LANcity Personal; Hybrid Networks Cable Client Modem 211; Zenith
HomeWorks Elite; Motorola CyberSurfr; General Instruments SURFboard
SB1000; Hewlett-Packard QuickBurst; Com21 ComPort; Toshiba and any
cable modem that conforms to the IEE 802.14 standard.
[0105] Typically, the IEEE 802.14 compliant cable modem genus will
contain species which have the following characteristics:
[0106] downstream data contained in one of the 6-MHz TV channels
that occupy the spectra above 550 MHz;
[0107] upstream channel assigned band between 5 and 45 MHz;
[0108] 64-QAM downstream modulation delivering over 30 Mbps data
rate;
[0109] upstream channel using QPSK modulation or a combination TDMA
and synchronous code division multiple access multiplexing
techniques and QAM modulation delivering from 2 to 10 Mbps in each
upstream channel;
[0110] a media access control software layer to mediate upstream
access between multiple users sharing the same cable medium;
[0111] a MAC protocol which is ATM friendly using the ATM cell
transport concept and possibly involving segmentation of ATM cells
into smaller segments to improve system performance;
[0112] status and control information looped back from the upstream
to the downstream to provide remote cable modems with status and
control information to determine pecking order;
[0113] the upstream channel divided into frequency channels that
are allocated to individual users or combining two multiplexing
methods such as TDMA and Synchronous CDMA or CDMA.
[0114] Cable modems within this genus include circuits and software
to achieve time synchronization where frame alignment is necessary
for proper demultiplexing. Although not required to be within the
genus, the better modems in the genus also include time
synchronization coupled with TDMA and CDMA to lower intersymbol
inteference as well as power alignment and adaptive equalization to
minimize other forms of interference. These better modems will also
include encryption such as pseudorandom scrambling or DES
encryption for privacy and a MAC layer protocol that insures
fairness in upstream bandwidth access.
[0115] These cable modems have been used to deliver residential
online subscription services that include Internet access, Email,
world news, shoppping, local content covering city government,
schools, libraries and other news of the community, multimedia
services, campus networking, distance learning and telemedicine,
internet access to schools, Prodigy, Jones Internet Channel and
work at home programs.
[0116] Details of Gateway Interfaces To Downstream Cable,
Satellite, And ADSL.
[0117] Referring to FIG. 4, there is shown a block diagram of one
embodiment of gateway 14 configured as a standalone circuit where
interfaces to the satellite, HFC and PSTN networks are all
implemented on the circuit board. This circuitry may be an
expansion card in a personal computer or it may be integrated into
the motherboard of a personal computer. The other known components
of the personal computer are not shown in FIG. 4 for simplicity,
but suffice it to say that the host CPU of the PC is coupled to
circuitry shown in FIG. 4 by the address, data and control buses of
the PC such that the circuits that need control inputs or data from
the host CPU may receive it. The control and data inputs needed by
each circuit will be described when that circuit is described.
[0118] The embodiment of the gateway 14 shown in FIG. 4 includes
the entire circuitry of a DOCSIS1.2 cable modem 70 therein. Turning
first to the interface circuitry to couple HFC to the LAN, HFC drop
line 10 is coupled to an upstream and downstream combiner and
isolation circuit 90. There, upstream modulated RF carrier signals
on line 92 from upstream isolation amplifier or coupler 94 are
coupled onto the cable 10 and downstream modulated RF signals are
received from cable 10 and placed on line 96. Typically, combiner
90 will include a bandpass filter to prevent upstream RF signals
from entering line 96 and may optionally include a termination for
line 92 to prevent reflections. Isolation circuit 98, typically a
buffer amplfier or capacitor or other circuitry such as a lighting
arrester protects the internal circuitry of the gateway from any
unwanted DC signals or lightning strikes on the HFC.
[0119] In the embodiment shown in FIG. 4, three tuners 100, 102 and
104 are used. Tuner 100 is tuned to one of the conventional CATV
analog video channels in NTSC, PAL or SECAM format. Typically, the
total bandwidth of the HFC will be divided up into different
frequency bands for CATV FDMA analog video channels, an upstream
DOCSIS data and management and control signals band, a digital VOD
signals band and a downstream DOCSIS data band. The frequency band
for upstream data and management and control signals extends from 0
to about 50 MHz. Within this band, upstream DOCSIS data will be
modulated onto one carrier frequency and management and control
data will be modulated onto another carrier frequency. There may be
multiple upstream management and control channels at different
frequencies or in different timeslots or on the same frequency with
the data of each management and control channel having its spectrum
spread with a different spreading code. Typically, the frequency
band from 50 to 500 MHz will be reserved for FDMA 6 MHz wide analog
CATV video signals. Digital video data such as for VOD or
teleconferencing etc. is typically modulated onto one of a
plurality of different frequency channels in a band above 500 MHz
with each channel being about 6 MHz wide and containing a plurality
of video, audio and associated data subchannels separated by TDMA.
Downstream DOCSIS data such as web pages which are downloaded
during high speed internet access is typically modulated onto a
carrier having a frequency somewhere above the video on demand
carrier frequencies.
[0120] One of the functions of the gateway 14 is to deliver
requested services to all the peripherals in the customer premises
seemlessly over a shared LAN thereby eliminating the need for
separate coaxial cable wiring to deliver CATV analog signals, a
digital network to deliver digital data, telephone wires to deliver
conventional telephone service. All these services are delivered
via a single digital data distribution system comprised of one or
more LANs. To that end, even CATV signals that are analog when they
arrive are digitized, compressed, turned into IP packets and then
into Ethernet packets and transmitted to the various televisions
via a LAN.
[0121] Reception and Distribution of Analog CATV Signals
[0122] Tuner 100 starts this process by receiving control data from
microprocessor 128 defining which CATV analog video channel which
has been requested. Users request analog CATV broadcast channels
via their IR keyboards 34 or remote controls 80 in FIG. 3. These
requests are encapsulated into management and control Ethernet
packets addressed to host CPU 128 by network adapter 30. The host
CPU receives them and generates a bus packet on bus 156 addressed
to tuner 100 telling it which channel to tune. The host bus 156 may
be a PCI bus in a Windows based personal computer, but high traffic
loads may bring such a bus to its knees since only two devices may
use the bus to communicate at any particular time. In alternative
embodiments, a high capacity multiplexed bus like an H.100 standard
TDMA bus coupled by suitable bus drivers to the host bus in a
computer with sufficient expansion slots for all the necessary
expansion modules to implement a flexible gateway may be used. In
other words, in smaller bandwidth consumption embodiments where
only one or two of the expansion modules shown in FIG. 8 are
present, a Windows based personal computer with a PCI or ISA bus
and one or two expansion slots may be sufficient. However, in
higher bandwidth consumption embodiments where many or all of the
expansion modules shown in FIG. 8 are present or might be added as
the number of services and external networks to be used grows, the
gateway 14 may also take the configuration of one or more personal
computers, each with a fast microprocessor and a PCI or some other
fast bus, each running one or more of the software processes
symbolized by FIG. 8 to divide up the labor. These servers would be
coupled to the LANs by one or more NICs with their one or more host
buses coupled to another expansion module interface circuit board
by one or more high capacity buses such as an H.100 TDMA bus, a
Firewire or even FDDI or Fibre Channel Arbitrated Loop LAN
technology. The expansion module interface circuit board would have
a plurality of expansion slots interfaced to the high capacity
bus(es) or LAN(s) coupling the expansion module interface circuit
board to the one or more servers. Each expansion slot would be
available to couple one of the expansion modules shown in FIG. 8 to
the shared software and hardware facilities of the servers. For
simplicity of expression, all of these various alternative bus or
LAN type interconnections between the server(s) and the modules in
the expansion slots will be simply referred to as the host bus or
the PCI bus 156. There will also be descriptions of circuits to the
effect of placing data in PCI bus or host bus packets addressed to
a particular circuit to which they are to be sent such as the IP
video circuit 158 or the routing process 86. This is to be
understood as actually placing the data into a packet with a
destination address set to the destination circuit or process or
seizing control of the host bus and writing the address of the
destination circuit onto its control lines and placing the data to
be transferred on the data lines and activating any necessary
control signals to latch the address and strobe the data into a
data register or other memory.
[0123] The RF output of tuner 100 on bus 134 is then digitized by
an analog-to-digital converter in A/D matrix 130. The digital
samples on line 136 are input to a video demodulator 138 which
functions in the digital domain to demodulate the digitized analog
video signal by removing the RF component. The video demodulator
138 outputs digital data on line 166 which represents a
conventional baseband NTSC, PAL or SECAM format video signal.
[0124] The digital data on line 166 is at too high a bit rate to
send over the LAN since uncompressed broadcast video is at 221
Mbps. Therefore, the video data must be compressed. MPEG II
compression is preferred, but any known form of compression
currently known or to be developed in the future will suffice since
the form of compression is not critical. MPEG II compression
circuitry is well known, and is used for MPEG encoder 146. However,
MPEG compression does not compress NTSC, PAL or SECAM format
signals. They must first be converted to YUV format luminance and
chrominance signals. This conversion is done in video decoder 142,
which is a known type of circuit in any video system that uses MPEG
II compression.
[0125] The compressed video data is encapsulated into PCI (or other
type) bus packets addressed to IP video circuit 158. There, the
compressed video data is encapsulated into IP packets addressed to
the network adapter of the TV where the CATV video channel is to be
viewed. The IP video circuit 158 determines which IP destination
address to use in constructing the IP packets via data received
from the host microprocessor 128. When the original request was
received, the host microprocessor 128, in addition to telling the
tuner 100 which channel to tune, also determines from the Ethernet
packet source address which TV's network adapter requested the
data. The IP address of this network adapter is encapsulated into a
PCI bus packet and transmitted via host bus 156 to the IP video
circuit. The IP packets encapsulating the digitized CATV channel
are then transmitted via bus 160 to the routing process 86.
[0126] The routing process 86 is a conventional IP to Ethernet
routing process which examines the IP packet destination addresses
and looks up the corresponding Ethernet addresses. The IP packets
are then encapsulated into Ethernet packets and routed to the
appropriate LAN network interface card for LAN 18 or 20 depending
upon the Ethernet destination address of each packet. The process
works in reverse for incoming Ethernet packets from the LAN(s).
[0127] When the IP packets reach the network adapter of the TV that
requested the CATV channel, they are converted to a video signal
that can be displayed by the TV by the circuitry described below in
conjunction with the discussion of FIG. 5.
[0128] Video on Demand
[0129] One disadvantage of watching CATV broadcast channels is that
there is no facility to have VCR like controls such as pause,
rewind, play, slow motion or stop over the incoming video. This is
one reason why VOD is more advantageous. We turn now to an overview
discussion of VOD delivered via cable modem. Later, VOD delivered
by ADSL modem or satellite dish will be discussed. The discussions
herein regarding delivery of VOD however apply equally to delivery
of video conferencing services, home shopping, distance learning
and other multimedia services involving video, images or other
multimedia data. Also, there is great similarity in the functions
and structure of the circuitry for receiving, recovering and
distributing digital VOD via satellite so there will be some
seeming replication of the discussions that follow. First, a quick
overview.
[0130] The VOD downstream frequency band has multiple video
channels, each at a different carrier frequency. Each video channel
carries multiple TDMA channels of MPEG II compressed video with its
associated audio, and sometimes with one or more additional TDMA
subchannels devoted to associated data.
[0131] The tuner 102 is commanded by the host microprocessor 128 to
tune to a particular VOD channel. The customer will order a
particular VOD program using the IR keyboard 34 or remote control
80. The microprocessor 128 receives the order information via
management and control Ethernet packets generated by the network
adapter 30 and driven onto the LAN 20. As an example of how the
video, audio and associated data subchannels of a VOD program are
used, suppose the tuner 102 is tuned to a home shopping VOD channel
where a plurality of customers wish to buy an item being shown by
the video data on a first subchannel and being described on the
associated audio data subchannel, there may be multiple customers
who wish to buy the item who need to talk to an operator. These
multiple customers can have their telephone calls digitized into IP
packets on digital telephones such as 62 in FIG. 1 with each packet
addressed to the IP address corresponding to the telephone number
shown on the screen. These packets get encapsulated into Ethernet
packets and transmitted on the LAN 18 or 20 to the gateway 14.
There, they are received by the switching process 86 and the
Ethernet headers are stripped and the IP packets are sent to DOCSIS
modem for transmission on an upstream channel.
[0132] At the headend modem, the IP telephony packets are recovered
and routed to the IP address where the operators are standing by.
Suppose, three callers are calling to buy the item being shown and
described. The three different operators handling these calls have
their speech digitized into IP packets addressed to the digital
telephone being used by the caller they are talking to. These IP
packets addressed to the telephones of the three different callers
are QAM modulated by the headend modem modulator transmitting the
VOD program and sent downstream as associated data on three
different TDMA subchannels associated with the video and audio
subchannels of the home shopping presentation.
[0133] The host microprocessor 128 tells tuner 102 which channel in
the VOD band to tune to via control data transmitted via data,
address and control bus 156 (also referred to as the host bus). The
RF tuner 102 tunes to that channel and rejects all other
signals.
[0134] The RF output of the tuner 102 is digitized by A/D matrix
130.
[0135] Then the video, audio and associated values for each video,
audio and data QAM modulated constellation point is recovered by
the QAM demodulator 146.
[0136] The recovered data values are then separated by transport
demultiplexer 148 into video, audio and associated data streams on
lines 150, 152 and 154. The transport demultiplexer receives
control data from the host microprocessor via data, address and
control bus 156 which tells it which subchannels to separate out in
the demultiplexing process.
[0137] A conventional conditional access circuit 126 then decrypts
the recovered data to prevent any unauthorized access thereto. The
decryption process can be the same process used in current Ku band
satellite digital video delivery or any other conventional
encryption process. Since VOD subchannels are sent to only
particular users, the data can be encrypted by PGP using the public
key of the user to which the data is directed. That user then uses
her private key to decrypt the data.
[0138] The conditional access circuit has a conventional PCI or
other bus interface circuit. Typically the gateway is implemented
as one or more circuit boards on a personal computer such as a
Pentium class or PowerPC Macintosh which has a system bus. Any
system bus which is fast enough to carry the worst case system load
bit rate will suffice. The worst case system load is based upon the
number and type of peripherals in the house. Typically, a
compressed digital video channel can be delivered with good picture
quality at 2 Mbps, so if a household has 4 TVs all of which are
tuned to a different VOD channel and one video conference going on,
10 Mbps should be adequate. PCI buses have maximum bit rates much
above 10 Mbps so a PCI bus for system bus 156 is adequate for most
applications. The conditional access circuit's bus interface
packetizes the decrypted video, audio and associated data into PCI
bus packets which are addressed to an IP video circuit 158 and
placed on bus 156 via line 160.
[0139] The IP video circuit receives the PCI bus packets and
encapsulates the video and audio data into IP packets addressed to
the network adapter 30 which ordered the VOD program. The
associated data is encapsulated into IP packets addressed to
telephone 62 (or whatever telephone is being used to converse with
the operator). The IP packets are then transmitted via line 160 to
the routing procss 86.
[0140] The routing process 86 is a conventional IP to Ethernet
routing process which examines the IP packet destination addresses
and looks up the corresponding Ethernet addresses. The IP packets
are then encapsulated into Ethernet packets and routed to the
appropriate LAN network interface card for LAN 18 or 20 depending
upon the Ethernet destination address of each packet. The process
works in reverse for incoming Ethernet packets from the LAN(s).
[0141] We now turn to a more detailed discussion of the process
carried out by the system to receive VOD via either satellite, HFC
or ADSL.
[0142] FIGS. 6A-6? together comprise a flowchart of the preferred
embodiment of the processing which occurs in the system to order a
VOD selection via either HFC, satellite or ADSL modem. Referring
jointly to FIGS. 4A and 4B, 5 and 6A-6?, a user orders a particular
video program via the IR keyboard 34 or remote control 80 acting as
a pointing device to point to a displayed menu selection on TV 28
in FIG. 3. That selection is received by the IR or RF receiver 82
in FIG. 5, as symbolized by step 106 in FIG. 6A. The video
selection along with the IP address of network adapter 30 is
encapsulated in an IP packet and then encapsulated in an Ethernet
packet by network adapter 30 and launched onto LAN 20 (step 108).
The IP packet has the IP address of network adapter 30 as its
source address and the IP address of the VOD server as its
destination address. The IP address will usually be different
depending upon whether the VOD selection has been ordered via HFC,
satellite or ADSL since each network probably has its own video
server. The user typically picks the VOD selection from a menu
displayed on her screen for each network, so by pointing to the
desired selection on the menu of the ADSL network, for example, the
IP address is set to the IP address of the video server for the
ADSL network.
[0143] The network adapter encapsulates the IP packet requesting
the video selection in an Ethernet packet (step 108). The Ethernet
packet destination address is the routing process 86 in the
gateway. The IP packet payload message identifies the movie or
other video program desired and, in some embodiments, identifies
the particular VOD channel and subchannel the gateway's VOD tuner
will be tuned to (step 108). MPEG II compressed video is
transmitted on two or more subchannels (one video, one associated
data and zero or more associated video subchannels), and this is
done regardless of whether the delivery media is HFC, satellite or
ADSL. Step 108 represents the preferred process wherein the headend
of the HFC, satellite network or ADSL central office monitors the
channels and subchannels for load and sends downstream load
balancing messages indicating which channels and subchannels are
free. These load balancing messages are monitored by the gateways,
and the channels and subchannels that are available are selected by
the gateways for "camping" thereby helping balance the load across
the network. In other embodiments however, the video server and/or
headend may simply put the requested video selection on any unused
subchannels of a channel that is not fully occupied and sends a
downstream management and control message to the gateway from which
the request originated indicating where the requested video
selection will be found. The host microprocessor 128 in the gateway
then sends data to its circuitry to cause the right channel to be
tuned and the right subchannels to be demultiplexed. The
"subchannel" means the particular timeslots or spreading codes to
use in receiving the video data when tuned to the frequency of the
"channel". In embodiments where only one video subchannel per
channel is carried, then subchannel and channel mean the same
thing.
[0144] In the preferred embodiment, the headend modem (or other
headend circuitry such as the uplink transmitting center in the
case of satellite or the ADSL central office--hereafter these other
headend circuits will be referred to as headend modems for brevity)
has a plurality of VOD modulators/transmitters (hereafter called
modulators), each of which is coupled to the VOD server and each of
which receives a plurality of streams of MPEG II compressed video
data. Each modulator is structured to transmit one VOD channel
downstream with the plurality of MPEG II compressed
video/audio/associated data streams being multiplexed therein by
TDMA, CDMA or Synchronous CDMA.
[0145] To implement the preferred form of load balancing, the
headend modem keeps track of which subchannels of each downstream
VOD channel are in use. It then broadcasts management and control
messages to all gateways via the HFC, satellite downlink or ADSL
lines of subscribers indicating which VOD channels and subchannels
are available and which upstream channels the gateways are to use
in sending messages that indicate that a gateway has "camped" on a
particular channel and subchannel.
[0146] The meaning of the term "camped" or "camping" is as follows.
The gateways receive these broadcast load balancing messages and
the host CPU of each gateway with a pending VOD request commands
their VOD tuners (such as tuners 102 or 180 or a corresponding
tuner in ADSL modem 182 in FIG. 4A) to tune to a channel that has
an available subchannel, as symbolized by step 108. The host CPU
then commands the appropriate transport demultiplexer (e.g.,
demultiplexer 114 for HFC delivery or demultiplexer 184 in the case
of satellite or a similar but not shown demultiplexer in the ADSL
modem 182) to demultiplex and select out only the compressed video
and audio data subchannels carrying the requested program as well
as the associated data subchannels. "Camped" or "Camping" therefore
means tuning of the appropriate digital VOD tuners and transport
demultiplexers in the gateway to a particular channel and
subchannel.
[0147] The channel and subchannel camping information is included
by the gateway in the IP packet bearing the upstream video request,
or is included within a separate IP packet generated by the gateway
that refers to the IP packet bearing the VOD request, also as
symbolized by step 108. This camping data aids the video server or
router in the headend modem (or the corresponding circuitry in a
satellite or ADSL VOD network) to get the requested video data to
the correct modulator which is transmitting on the VOD channel to
which the gateway coupled to the requesting IP address is tuned.
The channel and subchannel data included in the upstream message is
also used to control that modulator to put the video and associated
audio data on the subchannel to which the gateway is tuned.
[0148] Continuing with the discussion of FIG. 6A, the Ethernet
packet is received by switching process 86 (after it passes through
the network adapter card of the host computer and up through the
Ethernet protocol layers where the Ethernet header is stripped off
as symbolized by step 110). The switching process looks up the
destination address of the IP packet in a lookup table and
determines from the destination address of the IP packet that it is
directed to a VOD server coupled to the headend modem driving HFC
10 or the headend circuitry driving the uplink to the satellite or
to the ADSL central office (step 112).
[0149] Step 116 represents the general process of transmitting the
IP packet containing the VOD program request to the appropriate
video server over the appropriate transmission media. The following
paragraphs discuss the various cases individually, and step 116 is
to be interpreted as covering each of these individual cases
depending upon which video server is addressed by the IP packet.
The following discussion assumes the gateway is equipped with HFC,
satellite and ADSL expansion modules so that VOD can be ordered
from any of these three networks. The gateway however may have only
some subcombination of one or more of the HFC, satellite or ADSL
modem expansion cards, so step 116 will only represent routing the
IP request packet to one video server or possibly a selected one of
two different video servers delivering VOD over two different
networks.
[0150] In the case of an IP request packet addressed to a video
server coupled to the HFC 10 via the headend modem for delivery of
a VOD selection via the HFC, step 116 represents the following
subprocess. The IP packet gets routed to DOCSIS modem 70 and
transmitted on an upstream management and control channel. In the
preferred embodiment, the management and control channel used to
transmit the upstream request is the channel designated in a
downstream load balancing message from the headend modem indicating
which channels and subchannels are available and which upstream
channels the gateways are to use in indicating they have camped on
one of the available channels and subchannels. The IP packet is
recovered from the HFC and coupled directly or via the internet to
the video server to which it is addressed. The video server may be
coupled directly to headend modem or indirectly via the internet in
which case the IP request packet is sent by a router at the headend
over the internet to the video server.
[0151] In the case of an IP request packet addressed to a video
server coupled to the satellite uplink headend circuitry, the
upstream channel is over the PSTN so step 116 represents the
following. The IP packet get routed to the ADSL modem 182 or the
DOCSIS modem 70 for upstream transmission over the phone lines. If
routed to the ADSL modem, it transmits the IP packet request
message upstream over the PSTN lines to the ADSL central office
where it gets routed to the video server coupled to the satellite
uplink over a connection to the internet at the CO or a dial-up
connection over the PSTN to the video server directly.
[0152] If the IP packet addressed to a video server that delivers
VOD over the satellite network is routed to the DOCSIS modem, the
IP packet gets transmitted over the HFC to the headend DOCFSIS
modem. There, the packet gets recovered and reassembled (if
necessary) and sent to a router for delivery over the internet or
other WAN to the video server to which the packet is addressed.
Alternatively, the headend DOCSIS modem may make a dial up
connection over the PSTN to the video server or use IP telephony to
deliver the packet to the video server over the internet via IP
telephony circuitry coupled to the internet at the video
server.
[0153] If the IP VOD request packet is addressed to a video server
that delivers via ADSL, step 116 represents the following. Routing
process 86 routs the IP packet to the ADSL modem 182 where it is
transmitted via the ADSL upstream channel to the ADSL modem at the
CO. The CO then routes the IP VOD request packet to a video server
directly coupled to the CO or gives it to a router connected to the
internet for routing to a video server coupled to the CO via the
internet (the term internet means the internet or any other wide
area network currently in existence or which may come into
existence in the future). Alternatively, the CO may make a dial up
connection to the video server over the PSTN and send the IP VOD
request packet over the dial up connection or may communicate with
another CO where a video server is located by a T1 line or DS1 or
other high speed telephone lines. The processing and circuitry for
ADSL delivery of video demand taught in U.S. Pat. No. 5,247,347 may
be used, and that patent is hereby incorporated by reference.
[0154] Step 120 represents the optional step of authentication
and/or conditional access gating carried out at the headend prior
to routing the IP request packet to the video server. In some
embodiments, the IP packet bearing the VOD request is routed to the
video server only if the user making the request is authenticated
and/or is an authorized subscriber to the requested service. This
is typically by using the source address as a search key to search
a lookup table of authorized users. The manner in which the
requested services such as VOD are monitored so that they are
delivered only to authorized subscribers is not critical to the
invention, and the lookup function mentioned as part of step 120
can be replaced with any known manner of gating services only to
authorized users. The gating function can also be done at the
gateways after transmission of the VOD data downstream, and the
gateway 14 shows conditional access modules 126 and 186
representing these embodiments. In these embodiments where the
conditional access gating function is performed at the gateway,
step 120 is not needed. Processes for performing conditional access
gating at the customer premises are well known in C band and Ku
band subscription-based analog and digital video broadcasting, and
need not be detailed here. To implement this known type of
conditional access at the consumer premises, each gateway has a
decryption module (126, 186 and similar circuitry in ADSL modem
182) with a key or password stored therein. This key or password is
used by the video server or other service provider to encrypt the
VOD data or other data encoding the requested service using the
authorized subscriber's public key. Only that subscriber can
decrypt the data using his private key. The conditional access
modules 126 and 186 in FIG. 4A are intended to symbolize any of
these known prior art structures and processes for blocking access
by unauthorized persons to services.
[0155] After the IP packet reaches the video server, it reads the
IP packet and opens the file storing the data of the requested
movie or other video production (step 124). The video server then
begins transmitting the video data as IP packets addressed to the
TV and network adapter 30 that requested the movie (step 124). The
IP packets contain compressed video data, typically by MPEG II
compression. Step 124 is intended to represent one of the following
three subprocesses of delivery of the video data bearing IP packets
depending upon the video server to which the original IP packet
bearing the VOD request was directed and whether the IP video data
packets are to be delivered over HFC, via satellite or via a DSL
connection. Step 124 is not intended to represent delivery of the
VOD data by all three networks. The discussion of each subprocess
is labeled by a header, and three different lines of steps are
shown in FIGS. 6A-6? for the three different delivery networks
since each delivery network is coupled to different circuitry in
the gateway 14.
[0156] First, in the case of HFC delivery, step 124 represents the
process of transmitting the IP VOD packets to the modulator in the
headend modem which is transmitting downstream on the channel
identified in the original request packet. Transmission to this
modulator can be by a local direct connection, or via the internet
or other WAN or by a T1 or DS1 leased line or possibly by other
high speed PSTN connection such as DSL.
[0157] The video data is compressed in any known manner and is
encrypted before transmission. The preferred manner of implementing
conditional access is to do the gating function at the video server
end of the connection to avoid wasting downstream bandwidth on
requests by unauthorized users.
[0158] In the HFC delivery case, the compressed video and audio
data (and possibly associated data such as IP telephony packets) is
transmitted by the headend on the channel and subchannels
identified in the camping data given in the original request
message and arrives at the gateway 14 via line 10 (step 136). In
alternative embodiments, the video server and headend will
cooperate to put the VOD data on unused subchannels of a channel
that is not fully utilized and send a downstream management and
control message telling the gateway where to find the VOD program
it requested (step 136).
[0159] Upon reaching the gateway on the HFC connection 10, the RF
downstream signal is coupled through coupler 90 to buffer/isolation
circuit 98 and reaches tuners 100, 102 and 104. Tuners 100 and 104
reject it because they have been instructed by the host CPU 128 of
the gateway to listen on the analog video and DOCSIS data carrier
frequencies, respectively. Tuner 102 however has been instructed by
host microprocessor 128 (hereafter, the "host") to tune to the
channel on which the VOD data is modulated. In tuner 102, the RF
signal is received the RF component is removed and, a baseband
signal is output on line 190. In some embodiments, the tuner 102
outputs an IF signal on line 190 which is digitized in A/D matrix
130 with the IF mixed down to baseband by QAM demodulator 146 prior
to demodulation of the constellation points. Also, in some
embodiments, conventional carrier recovery and clock recovery is
performed in tuner 102, and the RF component is removed using a
local carrier synchronized in frequency and phase with the
transmitter's carriers to reduce the RF signal to I and Q baseband
signals on lines 190 and 191.
[0160] The VOD data bearing RF carrier is QAM modulated, so the
tuner outputs a complex analog baseband signal on line 190 with an
inphase and a quadrature component, each having multiple sample
periods each of which defines the I and Q values for one
constellation point. Both components are sent to A/D matrix 130 for
sampling with one sample per constellation point on each of the I
and Q signals.
[0161] The A/D matrix is comprised of either two or three A/D
converters depending upon whether the DOCSIS modem 70 has A/D
conversion circuitry therein. Typically, it does, so the output of
the DOCSIS data tuner 104 on line 132 is shown as passing the
baseband signal straight through the matrix 130 without any
sampling thereby.
[0162] The samples of the baseband analog I and Q signals on lines
190 and 191 containing VOD data constellation points are output on
bus 136. The process of receiving the RF downstream VOD signal and
demodulating and digitizing each constellation point's I and Q
values is symbolized by step 136. In the preferred embodiment, the
clock signal embedded in the data (or transmitted on a separate
channel in some embodiments) defining the boundaries of each
constellation point is recovered by tuner 100 and is made available
to any of the other circuits that need it to deal with the video
data.
[0163] The digitized, compressed VOD data is typically QAM-64
modulated. This means that the video and audio data is transmitted
in the form of constellation points each point transmitted during a
different time on the quadrature carriers with video, audio and
associated data constellation points transmitted during different
timeslots on the same channel. Each vidoe, audio or associated data
point takes the form of a complex number having a phase and an
amplitude value. QAM demodulator 146 determines the complex value
of video, audio and corresponding data points of the compressed VOD
data that correspond to each constellation point (step 140).
[0164] Transport demultiplexer 148 functions to demultiplex the
video, audio and associated data points from their respective
subchannel timeslots (or codes in embodiments where the subchannels
are CDMA multiplexed)as symbolized by step 144. The video
demultiplexer receives a control data input from the microprocessor
128 that tells the demultiplexer which subchannel timeslots (or
codes) to use in retrieving the requested VOD data.
[0165] The retrieved video, audio and associated data is output in
compressed form on buses 150, 152 and 154 to a conditional access
circuit 126. This optional circuit descrambles the data if the user
is authorized to receive the program ordered or does other known
types of conditional access gating if the conditional access
function has not already been done at the headend (step 192). If
the user is authorized to receive the VOD data, the video, audio
and associated data points are encapsulated into bus packets used
on the host bus 156 and sent over the bus to an IP video
encapsulation process 158. Typically, the host bus is a PCI bus so
known PCI bus interface circuits in conditional access circuit 126
encapsulate the VOD data into PCI bus packets addressed to the IP
video encapsulation circuitry (step 192).
[0166] The IP video circuitry monitors the bus 158 for packets
addressed to it and when it finds one, it takes the PCI bus packets
that together comprise an IP packet of VOD data and reassembles the
VOD data therein into and IP packet payload. In cases where the VOD
data was never put into an IP packet format at the headend, the VOD
video and audio data are assembled into IP packets addressed to the
network adapter that requested the VOD program. Any associated data
is encapsulated into an IP packet addressed to the appropriate
peripheral such as the PC 22 or the telephone 60 in FIG. 3.
Usually, the IP destination address to which the video, audio and
associated data are bound is included within the data itself, and
if an IP packet was broken up into, for example octets or ATM cells
for transmission, the original IP source and destination addresses
are preserved such as by the methods described previously
herein.
[0167] In the preferred embodiment, the IP source and destination
addresses in the IP packet data within the PCI bus packets are used
to assemble an IP packet header upon reassembly of the IP packet.
The resulting IP packets are transmitted over line 160 to the
routing process 86 (step 194). In embodiments where the VOD video,
audio and associated data was never placed into an IP packet
format, the host 128 keeps track of where each VOD request came
from on the LAN and the addresses of the video server to which each
is addressed. The when data arrives from that video server (as
determined by the source address of the data or the network,
channel and subchannel on which the data arrived), the host sends
data to the IP video circuit 158 telling it the IP address of the
network adapter the video and audio data are to be addressed to and
the IP address of any other peripheral to which any associated data
is to be sent. The case where the VOD data is not originally
encapsulated into an IP packet could happen where a video server is
coupled directly to a headend modem or a satellite uplink facility
or an ADSL CO. Step 194 is to be also interpreted as covering this
alternative case of constructing IP packets using IP addresses
supplied from the host 128 which is monitoring all outgoing VOD
requests.
[0168] The routing process 86 receives the VOD IP packets and reads
the IP destination address and determines that the IP address is
mapped to the Ethernet address of network adapter 30 in FIG. 3. The
IP packets addressed to this network adapter are then encapsulated
into Ethernet packets addressed to the network adapter 30 and sent
to the appropriate network interface circuit in routing circuitry
86 for launching onto LAN 20 (step 196). The household might have
multiple TV sets, each with its own network adapter. In such a
case, the IP destiantion address in the VOD data will be used to
determine which network adapter ordered the program and that
network adapter's Ethernet address will be used in the Ethernet
packet headers of the Ethernet packets into which the VOD data IP
packets are encapsulated. The routing circuitry will then determine
which LAN and NIC to use to get the data to the right TV.
[0169] What happens to the VOD data when it gets to the network
adapter will be discussed below after the discussion of the ADSL
and satellite delivery cases.
[0170] DSL Network Delivery
[0171] In the case of ADSL delivery (or delivery by any digital
subscriber line service with adequate bandwidth), the IP packets
are transmitted from the video server to an ADSL central office
within approximately 3 miles of the subscriber by a T1 or DS1 line
typically although an ADSL downstream connection might be used if
the possible maximum load of VOD data being sent to this particular
CO is light enough (step 198, FIG. 6B).
[0172] From the ADSL central office, the video data IP packets are
FDMA multiplexed onto the ADSL downstream carrier and transmitted
to the gateway of the requesting subscriber via the appropriate
local loop. At the gateway, the IP packets arrive on the PSTN local
loop 58 and coupled through an isolation buffer 204 to the ADSL
modem 182(step 202).
[0173] The ADSL modem 182 is a conventional structure and recovers
the IP packets in conventional manner and outputs them on line 188
to the switching process. There, the IP packets bearing VOD data
are encapsulated in Ethernet packets addressed to the NIC of
network adapter 30 which ordered the video program and sent to the
appropriate NIC in routing circuitry 86 which interfaces to the LAN
to which the network adapter 30 which ordered the VOD program is
coupled (step 206).
[0174] In embodiments where only a single LAN is in use at the
customer premises, an ADLS modem 200 (shown in dashed lines to
indicate it is an alternative embodiment) with an Ethernet output
interface may be substituted for ADSL modem 182 with the ADSL modem
output coupled directly to the LAN.
[0175] Satellite Network Delivery
[0176] In the case of satellite delivery of the video data IP
packets, the video server for the satellite network delivers the
VOD data IP packets to the satellite uplink facility by any
suitable means such as a T1 or DS1 leased line or by direct
connection to the uplink transmitter if the video server is located
at the uplink facility (step 208).
[0177] The uplink facility modulates the IP packet data onto the
DirecPC uplink carrier or another carrier devoted to VOD
applications and transmits it to a geosynchronous satellite (step
210).
[0178] A transponder on the satellite then recovers the IP packets
and QPSK modulates them (or using some other suitable modulation
scheme) onto a DiretPC or VOD downlink carrier and transmits them
to all the dishes in its footprint area on the surface of the earth
(step 212).
[0179] Tuner 180 (FIG. 4A) receives the RF signal and does
conventional carrier and clock recovery so that the recovered
carrier and clock signals can be used in demodulating, detecting
and demultiplexing the signals as was the case for the preferred
embodiment of tuner 102. Tuner 180 receives data from host 128 via
host bus 156 that tells it which downstream channel to which it
should tune, and it tunes out all other RF signals. The VOD
downlink quadrature carriers are then demodulated and I and Q
baseband signals are output on lines 216 and 218 (step 214).
[0180] Analog to digital conversion can happen anywhere after the
tuner 180 and prior to the IP packetization circuit 158. However,
for parallelism with the HFC case, we will assume that A/D
conversion happens in the QPSK demodulator 220 prior to the
constellation point demodulation process. The recovered clock from
the tuner 180 is used to synchronize the demodulation and A/D
conversion processes in circuit 220. The I and Q values of the QPSK
constellation points are then demodulated to their original analog
or digital values to yield a stream of video, audio and associated
data points on bus 222 (step 224). If they are demodulated to
analog values, these analog values for the I and Q values of each
constellation point are later digitized.
[0181] The satellite VOD delivery system is much like the HFC
system in that video programs are delivered on channels each having
a different downlink frequency and each having a plurality of TDMA
orCDMA CDAM subchannels. It is the function of transport
demultiplexer 184 to receive data from host 128 telling it which
subchannels to recover and to demultiplex the video, audio and
associated data points from their respective subchannels (step
226). The transport demultiplexer 184 has any conventional TDMA or
CDMA demultiplexing structure that can receive data indicating
which subchannels to recover and recover them and can be the same
structure as transport demultiplexer 148.
[0182] The recovered video, audio and any associated data are
output to a conditional access circuit 186 via buses 228, 230 and
232. The optional conditional access circuit 186 functions to
decrypt or otherwise gate the VOD data to the subscriber who
requested it only if she is a legitimate subscriber and if this
gating function was not performed at the satellite uplink facility
or the video server (step 234). The conditional access circuit can
have any of the known structures to perform this function.
[0183] The conditional access circuit has a host bus interface
circuit (not separately shown) which functions to take the data
from the VOD IP packets (usually the IP packets bearing VOD data
are broken up for transmission over the channel)and encapsulate the
data into bus packets of the type used on the host bus 156, e.g.,
PCI bus packets. These packets are addressed to the IP video
circuit 158 (step 236).
[0184] The IP video circuit functions as previously described.
Basically, it takes packet addressed to it off the host bus 156 and
either reassembles the IP packet if it was originally an IP packet
but was broken up for transmission (such as into ATM cells) or
encapsulates the data into an IP packet if it never was in an IP
packet format (step 238). Presumably, the incoming VOD data
includes the IP destination address in it. However, in some
embodiments, the host 128 will tell the IP video circuit 158, "If
you receive data from conditional access circuit 186, it is to be
addressed to the IP address of network adapter xx which requested
it." One way or another, the IP video circuit 158 assembles an IP
packet header for each packet that tells the routing circuitry 86
where the packet is to be sent on the LAN. The resulting IP packets
are sent to the routing circuit 86 via bus 160 (step 238).
[0185] The routing circuit 86 looks up the Ethernet address bound
to the IP address, encapsulates each IP packet into an Ethernet
packet and routes it to the appropriate network interface circuitry
in router 86 for the LAN to which the network adapter is coupled
which ordered the VOD program (step 240).
[0186] Note that if there is associated data with the VOD program
which needs to go to the personal computer 22 or to IP telephone 60
in FIG. 3, that data has its IP address set to the PC or the
telephone as the case may be and the router 86 addresses the
Ethernet packets containing this associated data to the Ethernet
address of the PC or telephone or other peripheral as the case may
be and this is true regardless of whether the VOD data is delivered
by ADSL, HFC or satellite (steps 238 and 194).
[0187] The Network Adapter Structure and Subprocess for Video on
Demand Processing
[0188] Regardless of which network was used to transmit the VOD
program, the data that encodes the program has now been
encapsulated into Ethernet packets and put onto the LAN. A block
diagram of a typical network adapter 30 in FIG. 3 is shown in FIG.
5. The function of the network adapter is to pick the appropriate
Ethernet packets off the LAN, strip out the video and audio data
and convert it to an NTSC or PAL or SECAM signal or to a video
signal which can be fed into a video input of a TV.
[0189] Each network adapter has a network interface card 84 which
couples the network adapter to the physical media of the LAN.
Network interface circuits for Ethernets are well known, and will
not be described further herein. Each NIC on the LANs 18 and 20 has
a unique Ethernet address which maps to one or more IP addresses.
Thus, when an IP packet addressed to the IP address of network
adapter 30 arrives at the gateway, the gateway's routing tables
will map this IP address to the Ethernet address of the network
adapter. The entire IP packet, header and all, will then be
encapsulated into an Ethernet packet with the destination address
of the Ethernet packet being that of the network adapter.
[0190] All Ethernet packets are received by NIC 84, but only
packets addressed to the network adapter 30 are kept. When an
Ethernet packet addressed to network adapter 30 is received, it is
examined to determine if the Ethernet address matches the address
of the network adapter, and, if so, the packet is passed through
the Ethernet protocol stack where the Ethernet header is stripped
off and error detection and correction are done on the packet. The
resulting IP packet is then passed to the IP video circuit 242
(step 244). For outbound packets such as menu requests and VOD
request packets, the Ethernet protocol stack in NIC 84 performs the
CSMA/CD transmission and collision detection protocol and transmits
the packet on the LAN.
[0191] The IP packets from the NIC 84 are examined by the IP video
circuit 242 to determine if they are addressed to the network
adapter and whether they are graphics data or video data. The IP
packet header is stripped off and payloads of packets that contain
compressed video/audio data are transmitted as a bit stream to MPEG
decoder 246, and packets that contain graphics data are transmitted
as a bit stream to 2/3 D graphics circuit 83 (step 248). In some
embodiments, the menus will not be sent as separate data but will
simply be video frames which are digitized and compressed. In such
embodiments, bus 87 is not necessary.
[0192] The MPEG decoder 246 decompresses the compressed video and
audio data bits and generates and uncompressed audio bit stream on
line 250 and an uncompressed video bit stream on line 252 (step
258).
[0193] The audio bit stream is enhanced for stereo and filtered and
then converted to an analog signal in any conventional audio
processor 254 (step 258). In alternative embodiments, the
uncompressed audio data not processed to enhance it or convert it
to stereo or filter it and is simply converted to an audio
signal.
[0194] The data output on line 252 is a digitized YUV format video
signal. Video processor 256 filters the video signal to enhance it
(step 258). The combination of the video processor 256 and the 2/3
D Graphics circuit 83 are commercially available in integrated
circuit form from ATI or C.sup.3.
[0195] The digitized YUV format video signal on line 264 (or 252 if
video procesor 256 is not used, is converted by video encoder 260
into an NTSC, PAL, SECAM or composite format video signal which can
be displayed on a TV (step 262). If the output signal format is
composite video, the composite video signal is input to the TV's
video inputs via line 266 (step 262). Likewise, the audio processor
converts the digitized uncompressed audio data into an audio signal
on line 270 for coupling into the audio input of a TV (step 272).
If the output signal from the video encoder 260 is NTSC, PAL or
SECAM format, the signal is modulated onto an RF carrier at some
locally unused frequency such as channel 3 by a video modulator 276
(step 274).
[0196] Wideband Internet Access
[0197] Dial up internet connections through modems are very slow.
It is much more useful to surf the internet with a much wider
bandwidth at least downstream.
[0198] Referring to FIGS. 7A-7?, there is shown a flowchart of the
process of high bandwidth surfing of the internet using one of the
HFC, satellite delivered DirectPC or DSL networks. In step 278, the
personal computer 22 in FIG. 3 or network computer (hereafter
sometimes referred to as NC) 24 or 26 launches its browser and
enters a URL of a web page to be viewed. The network computers 24
and 26 do not have any local hard drives, so they execute their
browsers from the hard disk of the personal computer via known
techniques of executing shared software on a server over the
network or over a WAN such as the internet. Typically, the network
computers indicate which program they want to run by double
clicking an icon on their desktops. This action is converted to a
request to download the program from a server on the LAN or WAN
into the RAM of the network computer. This request is converted by
the NIC of the network computer into an Ethernet packet directed to
the server on the LAN. The server NIC picks up the packet, opens
the file, and generates one or more Ethernet packets directed to
the network computer which receives the packets and loads the
browser program or other application that needs internet access
into RAM and begins executing it.
[0199] If the program to be run is resident on a server on the
internet, the step of doubling clicking the icon of the program to
be run is converted by TCP/IP protocol software layers in the
network computer (typically stored in nonvolatile flash EEPROM or
ROM) into an IP packet addressed to the server storing the
application program to be run. The IP packet is then encapsulated
into an Ethernet packet by the NIC of the NC addressed to the
gateway 14. At the gateway, the Ethernet packet is received by the
NIC and the Ethernet headers are stripped off by the routing
process 86. The packet is then routed to the appropriate
transmitter for the upstream medium the user has a subscription for
or which is cheapest for internet access if the user has DSL,
satellite and HFC modules installed--or some combination thereof
(least cost routing process). In other words, the IP packet will be
routed to the DOCSIS modem 70 for upstream transmission over the
HFC 10 or to the ADSL modem 182 if the DSL service or to
conventional modem 280 (which may also be a conventional FAX/Data
modem) if satellite downloading service via DirectPC is to be used.
The IP packet is sent by one of these media to the headend, ADSL CO
or by dialup connection to the satellite uplink facility. At the
destination, the IP packet is recovered and routed by a router at
the destination to the internet server storing the application to
be executed.
[0200] The internet server then sends the program to be executed to
the network computer by encapsulating the data of the program into
IP packets addressed to the NC that reqeusted it. These IP packets
arrive at the gateway and are recovered by the DOCSIS modem, ADSL
modem or satellite reception circuitry to be described below and
sent to the routing process 86. There, they are encapsulated into
Ethernet packets addressed to the NIC of the NC that requested the
program and launched on the LAN. The NC receives the packets,
strips out the data of the program, stores in its RAM and begins
executing it.
[0201] The user then enters the URL of the web site she wants to
visit (step 278). The browser or other application then passes this
URL down to TCP/IP protocol software processes in execution on the
computer which turn the URL into an IP packet requesting that the
web page at that URL be downloaded to the computer that asked for
it, as identified by the source address of the IP packet (step
282). This IP packet is then encapsulated into an Ethernet packet
addressed to the gateway 14 by the NIC of the NC or PC (step
284).
[0202] The gateway's NIC (not shown separately in FIG. 4A) receives
the Ethernet packet, strips off the Ethernet header after error
detection and correction and passes the IP packet up to the routing
process layers. The router looks up the destination address in its
routing tables and forwards the packet to one of the upstream
transmitters (step 286). If the user has only one network interface
such as an HFC interface only or an ADSL interface only installed
(as determined by either a discovery process carried out by the
router or by configuration data), the IP packet is forwarded to
that upstream transmitter. However, if user has more than one
network interface installed, the router may forward the IP packet
to an upstream transmitter based upon any criteria such as user
choice as indicated by a management and control packet sent to the
gateway or a field in the IP packet, by a random or round robin
selection process or by a least cost routing algorithm that
automatically picks the cheapest service for widebandwidth internet
access. Step 286 is intended to represent any of these methods of
selecting the upstream transmitter.
[0203] If the upstream transmitter is the DOCSIS modem 70, the IP
packet is transmitted upstream over a virtual channel devoted to
this gateway or assigned to it on the fly by the headend. The
virtual channel can be established by TDMA, SCDMA or CDMA or
possibly by FDMA. The CO modem recovers the IP packet and passes it
to a router coupled to the headend (step 288).
[0204] If the upstream transmitter is the ADSL modem 182, the IP
packet is modulated onto the upstream carrier and transmitted over
the PSTN local loop 58 to the ADSL modem at the CO. There, it is
recovered and passed to a router coupled to the internet (step
288).
[0205] If the downstream medium is going to be the satellite
downlink, the upstream transmitter is the conventional modem 280.
This modem dials a modem at the satellite uplink facility and
transmits the IP packet thereto. The IP packet is recovered and
passed to a router coupled to the internet (step 288).
[0206] The router sends the IP packet to the web server at the URL
(step 290) which opens the web page identified in the URL and
begins sending the web page data back to the router as a series of
IP packets (step 292).
[0207] The IP packets arrive at the router and are sent to the
appropriate downstream transmitter. Step 294 is intended to
represent downstream transmission over any of the HFC, DSL or
satellite media. In the case of HFC delivery, the downstream
transmitter will be the headend modem. The headend modem will
either broadcast the IP packet on the downstream carrier to all
gateways or transmit it on a virtual downstream channel assigned to
the gateway at the premises of the PC or NC that requested the web
page (step 294).
[0208] If the downstream media is the satellite downlink, the
router sends the IP packets to the uplink transmitter which
transmits them to the satellite. A transponder on the satellite
receives the packets and re-broadcasts them on the downlink channel
(step 294).
[0209] If the downstream media is a DSL local loop, the router at
the CO sends the IP packets to the ADSL modem at the CO which
modulates them onto the downstream carrier (step 294)
[0210] Step 296 is represents the recovery of the IP packets at the
gateway, regardless of the downstream media, transmission to the
router, protocol conversion and routing and transmission out on the
appropriate LAN. The details of how this happens in the gateway for
each different downstream media follows.
[0211] In the case of HFC downstream delivery, tuner 104 filters
out all but the DOCSIS downstream carrier and removes the RF
component. The resulting baseband signal is passed through the A/D
matrix on line 132 to the DOCSIS modem 70. There, the IP packets
are recovered and sent to the routing circuit 86 via bus 300.
Although this is shown as a separate bus, it may actually be the
host bus 156 in some embodiments with the IP packets being sent to
host microprocessor 128 by encapsulation in PCI bus packets
addressed to the host. Likewise for all other buses shown in FIG.
4A going into or coming out of the routing circuit 86. The router
86 looks up the destination address in the IP packets and
determines they are addressed to PC 22 or one of NC 24 or 26. The
router then encapsulates the IP packets into Ethernet packets
addressed to the appropriate PC or NC and directs them to the NIC
for the proper LAN connected to the PC or NC that requested the
data (step 296).
[0212] In the case of satellite downstream delivery, tuner 302 in
FIG. 4B is directed by host 128 to tune to the DirectPC downstream
QPSK modulated carrier. The tuner rejects all other signals and
recovers the carrier and synchronizes a local oscillator to
generate two coherent reference signals which are phase and
frequency matched to the two quadrature carriers used to transmit
the downstream IP packets. These local reference signals supply two
correlators in the tuner, one for the inphase channel and one for
the quadrature channel. Each correlator is comprised of a
multiplier and an integrator. Digital QPSK transmission and
transmitters and receivers therefore as well as other modulation
and multiplexing schemes and carrier and clock recovery circuits
are described in Haykin, Communication Systems, 3rd Ed. (Wiley
& Sons 1994) ISBN 0-471-57178-8 which is hereby incorporated by
reference. The digital satellite receiver channel is not limited to
QPSK modulation, and any modulation and/or multiplexing scheme used
today or subsequently for downstream transmissions may be used with
suitable adjustments to the gateway satellite digital data
receiver.
[0213] The output of receiver 302 is coupled via I and 0 buses 306
and 310 to a QPSK demodulator 304 which functions to recover the IP
packet data and encapsulate it into bus packets for the host bus
addressed to the routing circuit 86. The QPSK demodulator 304 is
typically comprised of a decision device that receives the baseband
I and Q channel signals and compares them to decision threshold of
zero volts. If the I channel voltage is greater than zero, a
decision of logic 1 is made but if its voltage is less than zero, a
decision of logic 0 is made. If the Q channel voltage is greater
than zero, a decision of logic 1 is made but if its voltage is less
than zero, a decision of logic 0 is made. Finally, the two binary
bit sequences defining the IP packets coming out of the decision
circuit are recombined in a multiplexer in demodulator 304 and sent
to bus interface circuitry in demodulator 304 for encapsulation
into bus packets and transmission via bus 312 and the host bus 156
to the router 86. The router receives them, strips off the host bus
packet headers, looks up the IP destination address and finds they
are addressed to the PC 22 or one of the NCs. The IP packets are
then encapsulated into Ethernet packets (or whatever other packet
format is used on the LANs 18 or 20) addressed to the PC or NC that
ordered the data and sent to the proper NIC (step 296).
[0214] If the downstream media is an ADSL local loop, a
conventional ADSL modem 182 in FIG. 4A recovers the IP packets and
sends them on bus 188 to the router 86. The router receives them,
strips off the host bus packet headers (if bus 188 is actually the
host bus 156), looks up the IP destination address and finds they
are addressed to the PC 22 or one of the NCs. The IP packets are
then encapsulated into Ethernet packets (or whatever other packet
format is used on the LANs 18 or 20) addressed to the PC or NC that
ordered the data and sent to the proper NIC (step 296).
[0215] The NIC of the PC or NC that ordered the data receives the
Ethernet packets, does error correction and strips off the Ethernet
headers. The resulting IP packets are passed up the TCP/IP protocol
layers where the IP packet headers are stripped off and the TCP
protocol makes sure all the packets have been received. The payload
data is then sent to the application that requested it for display
(step 308). Processing by the PC or NC of the IP packet data and
Ethernet packets is the same as in PCs on a LAN that share modems
and dial up connections to the internet through ISPs, and that
technology is incorporated by reference.
[0216] Reception and Distribution of Analog Video Broadcasts Via
Satellite or Terrestial Antenna
[0217] One of the advantages of the gateway 14 is that it may also
be used to distribute analog TV broadcasts to TV's throughout the
house using the LAN thereby eliminating the need for separate
wiring.
[0218] Tuner 314 starts this process by receiving control data from
microprocessor 128 defining which C-band analog video channel has
been requested by the user. Tuner 314 can be any conventional
C-band satellite tuner modified so as to accept digital control
data from the host 128 to control which satellite and which
transponder to tune to as opposed to receiving this information
directly from a remote control or front panel switches. In the home
network described herein, users request C-band broadcast channels
via their IR keyboards 34 or remote controls 80 in FIG. 3. These
requests are encapsulated into management and control Ethernet
packets addressed to host CPU 128 by network adapter 30. The host
CPU receives them and generates a PCI bus packet on bus 156
addressed to tuner 314 telling it which channel to tune, i.e.,
which satellite to turn the dish to and which transponder or
channel in the downlink broadcast to tune to.
[0219] The RF (or IF) output of tuner 314 on bus 134 is then
digitized by an analog-to-digital converter 316. The digital
samples on line 318 are input to a video demodulator 320 which
functions in the digital domain to demodulate the digitized analog
video signal by removing the RF component. The video demodulator
320 outputs digital data on line 322 which represents a
conventional baseband NTSC, PAL or SECAM format video signal.
[0220] The digital data on line 322 is at too high a bit rate to
send over the LAN since uncompressed broadcast video consumes about
221 Mbps of bandwidth. Therefore, the video data must be
compressed. MPEG II compression is preferred, but any known form of
compression currently known or to be developed in the future will
suffice since the form of compression is not critical. MPEG II
compression circuitry is well known, and is used for MPEG encoder
326. However, MPEG compression does not compress NTSC, PAL or SECAM
format signals. They must first be converted to YUV format
luminance and chrominance signals. This conversion is done in video
decoder 324, which is a known type of circuit in any video system
that uses MPEG II compression.
[0221] The compressed video data is encapsulated into PCI (or other
type) bus packets addressed to IP video circuit 158 on FIG. 4A.
There, the compressed video data is encapsulated into IP packets
addressed to the network adapter of the TV where the request
originated and the satellite C-band video channel is to be viewed.
The IP video circuit 158 determines which IP destination address to
use in constructing the IP packets via data received from the host
microprocessor 128. When the original request was received, the
host microprocessor 128, in addition to telling the tuner 314 which
channel to tune, also determines from the source address of the
Ethernet packet bearing the request which TV's network adapter
requested the data. The IP address of this network adapter is
encapsulated into a PCI bus packet and transmitted via host bus 156
to the IP video circuit. The IP packets encapsulating the digitized
C-band video channel are then transmitted via bus 160 to the
routing circuit 86. Bus 160 may simply be the host bus 156 in
embodiments where the routing process is carried out in software on
the host 128.
[0222] The routing process 86 is a conventional IP to Ethernet
routing process which examines the IP packet destination addresses
and looks up the corresponding Ethernet addresses. The IP packets
are then encapsulated into Ethernet packets and routed to the
appropriate LAN network interface card for LAN 18 or 20 depending
upon the Ethernet destination address of each packet. The process
works in reverse for incoming Ethernet packets from the LAN(s).
[0223] When the IP packets reach the network adapter of the TV that
requested the CATV channel, they are converted to a video signal
that can be displayed by the TV by the circuitry described above in
conjunction with the discussion of FIG. 5.
[0224] Terrestial Broadcast Reception
[0225] Reception and distribution of standard TV broadcasts
received over an antenna coupled to the gateway 14 is very similar.
A standard TV antenna 328 is coupled to the gateway by a coax or
twinlead wire 330. A TV tuner 332 tunes the requested channel and
outputs the desired channel as an RF or IF signal. Tuner 332 can be
a conventional TV tuner modified to receive digital control data
from the host computer 128 which controls which analog TV broadcast
channel the tuner selects.
[0226] A/D converter 334 samples the output RF or IF and feeds the
samples to a video demodulator 336. There the signal is demodulated
in the digital domain to remove the RF component. As is the case
for all the analog signal receiver circuits for both HFC and
satellite, the analog-to-digital conversion can happen anywhere
along the line of circuits including just before the MPEG
encoder.
[0227] The output 338 is a digitized version of an NTSC or PAL or
SECAM signal. It is fed to a video decoder 340 which converts it to
a YUV format. The YUV signal is then compressed by MPEG encoder 342
and put into bus packets of the format used on the host bus 156
(typically PCI) and addressed to the IP video circuit 158.
[0228] The IP video circuit strips off the bus packet headers (and
may perform error detection and correction) and encapsulates the
compressed video data from the PCI bus packets into IP packets
addressed to the network adapter of the TV set where the requested
channel is to be viewed. The IP packets are then sent to the router
86 where the destination address is looked up and the IP packets
are encapsulated into Ethernet packets addressed to the same
network adapter and launched onto the appropriate LAN.
[0229] LAN Alternative Embodiments
[0230] Video is isochronous or stream-oriented. On the other hand,
traditional LAN traffic is more bursty. LANs were not developed to
support streaming traffic, and it is therefore possible that a 10
Mbps 10Base-T Ethernet LAN will not have sufficient bandwidth at
times to support the load, especially where there are multiple TVs
each requesting a different channel along with other simultaneous
traffic sharing the 10 Mbps bandwidth. Video is highly bandwidth
intensive so even 100 Mbps LANs have trouble supporting high
quality video intermingled with more traditional LAN data
traffic.
[0231] Accordingly, it is within the scope of the genus of the
invention to use higher capacity LANs for LANs 18 and 20.
Specifically, these LAN can be Fast Ethernet, Switched Ethernet,
FDDI, ATM and Fibre Channel Arbitrated Loop. Such LANs are
described in Tanenbaum and Horak, supra, and Kembel, Arbitrated
Loop, Connectivity Solutions, a division of Northwest Learning
Associates, Inc of Tucson, Ariz., (1997) ISBN 0-931836-82-4.
[0232] Reception and Distribution of DirecTV Digital Video
Broadcasts
[0233] The gateway will include a bus slot for a module which can
receive regularly scheduled DirecTV and other format digital video
broadcasts on downlinks from a satellite. A tuner 344 serves to
receive digital control information from host microprocessor as to
which channel on the downlink a user has requested. The tuner then
tunes to this channel and rejects all other signals and a QAM
demodulator demodulates the signal to recover the transmitted data
and outputs a complex baseband signal on line 348. Conventional QAM
modulated digital data receivers are taught in Lee &
Messerschmitt, Digital Communications, 2d Ed., (Kluwer Academic
Publishers 1994) ISBN0-7923-9391-0, Section 6.4.3, pp. 203-208 and
FIGS. 6-18 and 6-19, the entirety of this book being hereby
incorporated by reference. Typically, the tuner 344 will be
comprised of a bandpass filter to tune the desired channel and
reject out-of-band signals and doubling as an anti-aliasing filter.
Typically, the signal is then digitized and a phase splitter (a
filter that passes only frequency components in the positive half
of the Fourier spectrum and rejects Fourier components in the
negative half) acts in the discrete time domain to remove the
negative half Fourier frequency components of the received spectrum
to output an analytic signal. Then the positive half frequency
components of the received signals are demodulated, i.e., the RF
carrier component is removed by mixing with a local carrier which
is synchronized to the transmitted carrier.
[0234] FIG. 6-16 of Lee et al. at p.204 illustrates three different
configurations for a QAM tuner.
[0235] The function of the QAM demodulator 346 is to detect the
actual symbols sent. This is typically done by sampling and
slicing. A complete QAM tuner to get the receive signal back to
baseband and demodulator to recover the transmitted symbols is
shown in FIG. 6-18(b) of Lee & Messerschmitt for the real
valued case and is comprised of two mixers which move the received
spectrum back to baseband by multiplying by quadrature shifted
local carriers and two receive bandpass filters to reject out of
band signals and pass only the positive half Fourier components of
inphase and quadrature signals. The I and Q signals are then
sampled at the symbol rate and passed through a slicer to recover
the symbols actually transmitted. A more complete representation of
a practical QAM receiver including both precursor equalization and
postcursor equalization and carrier and timing recovery is shown in
FIG. 6-23 of Lee & Messerschmitt. Preferably there will also be
an error detection and correction circuit as well (not shown).
[0236] After the symbols of the compressed video program are
recovered, a conventional transport demultiplexer 350 receives
digital control input from the host as to which subchannel on which
to find the video program which has been ordered and demultiplexes
the audio, video and any associated data from those
subchannels.
[0237] To help manage the load on the LAN, an optional transcoder
352 is used to translate the bit rate of the compressed video down
to a lower rate when necessary because of current loading
conditions on the LAN. Transcoders are known and were commercially
available from Imedia in San Franscisco, Calif. and now from the
assignee of the present invention.
[0238] The output data of the transcoder is supplied to a
conventional conditional access circuit 354 which decrypts the data
if the subscriber is authorized to receive the program.
Alternatively, the conditional access circuit 354 may function to
decrypt the original encrypted data if the user is an authorized
subscriber and then re-encrypt the data before transmission on the
LAN using the new C5 encryption standard. The re-encrypted data is
then packetized into bus packets and transmitted over the host bus
156 to the IP video circuit 158. There it is encapsulated into IP
video packets addressed to the network adapter that requested the
program and sent over data path 160 to the routing circuit/process
86. The routing process looks up the destination address and maps
it to the LAN address of the network adapter and encapsulates the
data into Ethernet packets and sends them to the correct NIC for
transmission over the LAN. At the network adapter, the packets are
processed as previosuly described in connection with the
description of FIG. 5 to convert the data to NTSC, PAL or SECAM
video signals and the corresponding synchronized audio. If C5
encryption is used, the data remains encrypted at all stages until
it is converted to analog video and audio signals.
[0239] A conventional DirecTV receiver modified to receive digital
control data telling it which channel and subchannel to tune can be
substituted for tuner 344, QAM demodulator 346 and transport
demultiplexer 350. Alternatively, the satellite receiver taught in
U.S. Pat. No. 5,983,071 may be used but modified to remove the
audio decoder 160, the D/A converter 164, the video decoder 170 and
the NTSC encoder 174. Those functions all happen at the network
adapter after distribution over the LAN. If the receiver of U.S.
Pat. No. 5,983,071 is substituted for the tuner 344, QAM
demodulator 346 and transport demultiplexer 158 and the conditional
access circuit 354, the audio and video output stream on lines 162
and 172 of the patent will be supplied to the transcoder 352. The
receiver taught in U.S. Pat. No. 5,983,071 may also be used in
place of tuner 102, A/D matrix 130, QAM demodulator 146,
conditional access circuit 126 and transport demultiplexer 148.
Again, this receiver will be modified to remove the following
components taught in the patent: audio decoder 160, the D/A
converter 164, the video decoder 170 and the NTSC encoder 174.
Those functions all happen at the network adapter after
distribution over the LAN. A transcoder may also optionally
substituted into the HFC digital video receiver module circuit that
includes tuner 102, and the conditional access circuits 126 and 186
may both be modified as described above to re-encrypt the recovered
data under the C5 standard to prevent digital copies from being
made. If the receiver of U.S. Pat. No. 5,983,071 is substituted for
the tuner 102, QAM demodulator 130 and transport demultiplexer 148
and the conditional access circuit 126, the audio and video output
stream on lines 162 and 172 of the patent will be supplied to
either a transcoder, if present, or to bus interface circuitry (not
shown) which packetizes it and sends it to the IP video circuit 158
over the host bus.
[0240] Pay Per View Push Technology Gateway Compatibility
[0241] The gateway 14 can also be used to receive pay per view or
free regularly scheduled broadcasts of digital or analog video
programs. Push technology means a video server at or coupled to the
HFC headend, ADSL CO or satellite uplink has a regular schedule of
video programs that it outputs at specific times on specific
channels. A menu displayed on the television set in the manner
described elsewhere herein or publication is used by the user to
select the program the user wishes to view. The user selects the
program she wishes to view at the time the program is supposed to
start by entering the program number (the program number can be
mapped to the service provider and the video server IP address or
that information can be entered manually) on her remote control 80
or keyboard 34. That program number is encapsulated into an
Ethernet request packet and transmitted to the gateway where it is
routed to the host. The host 128 then sends the appropriate command
data over the host bus to tuner 102, or 100 or 180 or 314 or 344 or
332 or ADSL modem 182 to tune to the appropriate channel, depending
upon which medium the program will be arriving. In the case of
digital video, the host also sends control packets to the transport
demultiplexer 350 or 184 or 148 to control them to demultiplex the
compressed video and audio signals off the correct subchannels. If
transcoders are used in the digital or analog video receiver
modules, the host will monitor the monitor the load status of the
LAN in any known way and send appropriate control packets to the
transcoders over the host bus to control the bit rate of the
compressed video transmitted over the LAN so as to not exceed the
available bandwidth under varying load conditions.
[0242] IP Telephony
[0243] Since there is a LAN to runs throughout the customer
premises, it is useful to use the LAN to distribute video and audio
and FAX telephony data to the video phones, telephones, FAX
machines and FAX modems throughout the premises. Also, since all
these physical telephony devices are coupled to a computer, it is
useful to include an IP and/or PBX telephony module 352353 in the
gateway to provide functionality that the user could not formerly
obtain from POTS service. POTS service can provide conference
calling, call forwarding, caller ID, voice mail and pager
notification of voice mail messages as well as other services
through facilities such as Centrex provided by the CO switch.
However, these services all cost extra money, and can be
implemented locally in the gateway through use of "PBX on a card"
expansion circuitry to extend the functionality of the host. Such
telephony circuitry 352 to extend the functionality of DOS and
Windows based personal computers to include PBX functionality,
voice mail and a host of other features is commercially available
as the VS1 and Incline systems from Picazo Communications, Inc. of
San Jose, Calif. and from Netphone, Inc. of Marlborough, Mass., and
Altigen Communications, Inc., the details of which are hereby
incorporated by reference. The Netphone PBX on a card technology
which can be used to implement circuit 352 is described in U.S.
Pat. No. 5,875,234 which is hereby incorporated by reference. This
patent basically teaches a PBX circuit on an expansion card that is
coupled to the host bus of a network server. The PBX card can
establish and maintain telephone calls and do normal PBX call
control functions. The PBX card can be controlled from telephony
enabled applications on the server/gateway or by telephony enabled
applications running on PCs via the LAN connection to the gateway.
Any known expansion circuitry to add PBX functionality to a LAN
server regardless of whether it is implemented one one circuit
board or more than one may be used for circuit 352.
[0244] Typically, the circuit 352 will have its own switching
circuit for connecting phone calls from extension phones coupled to
conventional phone lines to CO trunk lines 58 and vice versa.
[0245] In some embodiments, the PBX functionality alone may be
sufficient. However, use of the internet for telephony is a growing
market, and websites such as www.net2phone.com already exist to
allow long distance telephone conversations to take place over the
internet regardless of distance for 10 cents per minute. To allow
users to take advantage of these services, PCs on LANs 18 and 20
will need to be equipped with microphones and speakers. In such a
class of embodiments, the IP & PBX telephony circuit 352 will
include circuitry to digitize analog voice signals arriving from
the extension phones via conventional phone lines 354. The IP &
PBX telephony circuit 352 may also include packetization circuitry
in some embodiments to receive Ethernet packets carrying digitized
voice from the PCs on LANs 18 or 20 from router 86 via bus 356 and
packetize them into IP packets addressed to the internet server
providing the IP telephony services. These IP packets are then sent
back over bus 356 to router 86 where they are routed to the server
identified in the destination address of the IP packet. The routing
can be least cost routing if multiple high bandwidth upstream media
such as HFC and ADSL upstream high speed internet access modules
such as DOCSIS modem 70 and ADSL modem 182 are present in the
gateway. In other embodiments, the PBX expansion module 352 will do
call control switching and provide other services between extension
lines 354 and the CO trunk lines, and analog telephone signals from
the extension phones on line 354 will be digitized and packetized
into an IP packet addressed to an IP telephony server on the
internet whose IP address is fixed and known to be the IP address
to which the telephone data from the conventional POTS telephones
is to be directed.
[0246] Then, instead of sending data from Ethernet packets bearing
telephony data from PCs, telephones and FAX machines on the LAN for
encapsulation into IP packets by the IP & PBX telephony module
352, the IP packet encapsulation will be done at the source. In
other words, if PC 22 or NC 24 or phone 60 or FAX 64 at the
customer premises wants to send data to an IP telephony server on
the internet, the digital data generated by the source device will
be encapsulated by the source device into IP packets addressed to
the IP telephony server on the internet. These packets will then be
encapsulated into Ethernet packets and sent to the gateway 14. The
gateway 14 will then strip off the Ethernet packet headers and rout
the enclosed IP packets to the server on the internet to which they
are addressed via the DOCSIS modem 70, the ADSL modem 182 or
possibly by the conventional modem 280 in FIG. 4A (although use of
the conventional modem would only make sense if higher bandwidth
upstream media was not available).
[0247] Modular Construction of Gateway
[0248] Referring to FIG. 8, there is shown a block diagram
illustrating the software architecture and modular construction of
the gateway/LAN server 14. As mentioned above, in alternative
embodiments, the gateway 14 may actually be comprised of two or
more servers to divide the labor but each coupled to the expansion
modules by a bus/LAN structure 156. For example, one server may run
only the PBX control software and IP telephony software and another
server may run only the management and control and routing process
needed for the push and pull video applications and high speed
internet access and perform any routing functions needed for IP
telephony by the first server.
[0249] The software processes in the host or server run in
conjunction with the operating system 358 and use its application
programmatic interfaces (API) for message transfers between
processes and to send data to the LAN interface or NIC 360 and the
host bus 156. The data paths between the various software processes
and between the various processes and NICs 362 and 364 and the host
bus 156 through the operating system are symbolized by data path
366. This data path represents any of the typical methods and
apparatus for transferring data between processes or between
processes and circuits in the gateway. For example, NIC #1 362 may
receive an Ethernet packet bearing a request for a video-on-demand
program that is addressed to the management and control process.
One way NIC 362 can transfer that packet to the routing process 86
by writing the data into on-board scratchpad RAM and invoking a
software interrupt for the routing process 86 and passing it a
pointer to the message in RAM. The routing process then executes an
interrupt service routine for that interrupt and reads the data
from the scratchpad RAM at the address passed with the interrupt or
at some preassigned address stored in an interrupt table. Processes
and circuits can also pass messages by writing them into
predetermined locations in shared address space in RAM 129 with the
destination circuit or process and then setting an interrupt bit
and storing an interrupt number in a register. The interrupt bit
causes the host to execute a generic interrupt service routine to
retrieve the interrupt number and then look up the interrupt number
in an interrupt vector table. The table would return the address of
the beginning of an interrupt service routine for that number. Each
circuit or process would have an interrupt number and an associated
interrupt service routine. The service routine pointed to by the
vector table would then be executed and retrieve the data and
return it to the process or circuit associated with that interrupt.
Each of the expansion modules could pass data or IP packets to the
routing process 86 or the IP video process 158 in that way.
[0250] A management and control process 368 receives
video-on-demand and other requests for services and data as
described in the detailed descriptions of each module. These other
requests can include the numbers of CATV or terrestial channels to
tune in or requests for DirecPC or ADSL or HFC high speed internet
access. Other data the management and control process will receive
in alternative embodiments is LAN available bandwidth status and
other network management type data. In response, the management and
control process sends out the appropriate control data to the
tuners, transport demultiplexers, transcoders, conditional access
circuits, IP video process and other circuits or processes to
manage retrieving the requested data and distributing it to the
right peripheral or to transmit data upstream on particular
upstream channels. These upstream channels may be preassigned or
assigned by downstream control messages from the headend or ADSL CO
or satellite uplink server.
[0251] The routing process 86 translates between IP and Ethernet or
other LAN protocols and functions as previously described. The IP
video process 158 encapsulates data sent to over the host bus into
IP packets addressed to the proper peripheral device.
[0252] The IP telephony and other telephony enabled and PBX
processes represented by block 370 control the IP and PBX telephony
expansion module to implement PBX functions, carry out IP telephony
etc. For example, there may be 5 conventional or LAN telephones in
the home each of which is primarily answered by one person in the
family. One of the processes of block 370 may implement direct
inward dialing such that each telephone has its own virtual
telephone number which an outsider can dial when, for example, they
want to talk to teenager Judy without the inconvenience of
accidently talking to her father. Likewise, two extension phones
may wish to have a conference call with a phone in some other
state. The PBX control sofware controls the switch in the PBX
module 372 to implement any of these desired PBX functions. The IP
telephony process carries out IP telephony, by, for example,
receiving digital data from conventional POTS phones via telephony
module 372 and encapsulates it into IP packets which are passed to
router 86 and vice versa. IP packets received from LAN enabled
telephones 60 and 62 are just passed directly to the router 86.
[0253] Likewise, a database program or word processing program
being run on a PC or NC out on the LAN may be telephony enabled.
For example, a rolodex file made by a word processing program may
contain telephone numbers and the user may look up a person by name
and then double click on the phone number. This double click will
be converted by the telephony enabled application into an Ethernet
packet requesting that the telephone number be dialed. This
Ethernet packet is sent to NIC 362 or 364 and is there passed up to
the router 86. The router strips the Ethernet header off and passes
the data of the request to a PBX application represented by block
370. The PBX application makes a function call to a library program
of the OS 358 through the standard TAPI interface 374.
[0254] The TAPI interface represents a collection of predefined
Windows function calls, each of which invokes a library program
from a telephony dynamic linked library of programs. The TAPI
function calls provide a standard telephony programmatic interface
to applications that want to perform telephone functions. The basic
level of functions allow application programs to carry out basic
inbound and outbound voice and data calls by providing programs
that can be invoked to initialize and open and close TAPI lines,
read and write various parameters that control a line device,
handle the details of placing an outbound voice or data call or
answer an inbound voice or data call, recognize, translate and or
build telephone "addresses" or dialing strings, manipulating call
handles etc. Other programs in the TAPI library provide more
advanced functions such as digit or tone generation and detection,
call acceptance and rejection, redirection, call forwarding, park,
hold, conference, etc. if the These advanced features are called
supplemental telephony services and allow multiple telephone
handsets or other line devices to share only a single CO trunk line
or to share multiple CO trunk lines in a PBX type arrangement. The
trunk lines can be analog, T1, ISDN or DSL. Because TAPI also
supports the logical construct of phone devices, the NCs and PCs
out on the network with TAPI libraries can actually have multi-line
virtual telephones implement in code running thereof so that every
room with a PC in it can also have a multi-line phone capable of
speakerphone, conference, hold, park, call forwarding and other
advanced capabilities not normally on standard home telephones.
[0255] TAPI services focus on "line devices" as a means for
transporting information from one place to another. A line device
can be a standard telephone handset, a fax board, a data modem, a
telephony card or any physical device coupled to a telephone line.
In the system depicted in FIG. 8, the ADSL modem module 378,
conventional modem module 380 and IP and PBX telephony module 372
are all line devices. Because a line device is a logical construct,
TAPI can see multiple line devices all coupled to the same physical
telephone line. A TAPI call control program (dialer.exe) can accept
multiple simultaneous TAPI service requests from, for example, the
PBX application, the IP telephony application and other telephony
enabled applications all represented by block 370 and queue them
all for service in order.
[0256] Communications between the application programs and the TAPI
library are by the Windows messaging function using predefined TAPI
data structures. Telephony libraries of other operating system may
be substituted for the Window TAPI library and the data structures
and and messaging functions of the operating system in use can be
substituted.
[0257] How TAPI is structured and how application programs can be
written to utilize this resource are all defined in Amundsen, MAPI,
SAPI & TAPI Developer's Guide, (SAMS Publishing 1996) ISBN
0-672-30928-9, which is hereby incorporated by reference.
[0258] Returning to the current example, the TAPI program executes
and makes a function call to the telephone service provider process
376 and passes it the number to be dialed. The TSP layer 376
isolates the TAPI library program from needing to know the details
of the specific hardware installed and it isolates the particular
hardware which is installed from having to be designed for the
specific telephony enabled application programs which are present.
It is translator between the TAPI world and the harware world. In
other words, the TSP layer 376 implements the TSPI fucntions that
are used by TAPI implementation. Each TSP then uses whatever
interface is appropriate to control the telephony hardware to which
it is connected. The TSP layer 376 and the PBX card driver layer
378 actually can be combined in some embodiments, and in other
embodiments, the TSP layer can be used to interface to other
telephony hardware such as a FAX modem expansion module 380 at the
gateway by which FAXes may be sent using data received from PCs
that do not have FAX modems or connections to telephone lines
available at their location on the network.
[0259] Assuming the TSP and PBX card drivers are separate
processes, either TSP 376 or TAPI program 374 then invokes the
proper function call of a PBX card driver process 378 and passes it
the number to be dialed. The PBX card driver speaks the specific
language of the IP and PBX telephony module 372 and sends it a
properly formatted message to control the switch and other
circuitry thereon to seize a CO trunk line and generate the
appropriate DTMF tones to dial the requested number when a dial
tone is detected.
[0260] When the person answers, the voice is digitized by a codec
in the PBX card 372 and and the data is passed back to the PBX card
driver which then passes it back up through all the layers to the
router. The router encapsulates the data into an Ethernet packet
addressed to the telephone or other line device that made the call
and passes the packets to the appropriate NIC. From the NIC, the
packets are transmitted via LAN to the network adapter of the
telephone or PC or NC that originated the call. The reverse thing
happens for voice going out from the PC, NC or telephone which
originated the call to the person who answered the phone.
[0261] The host bus is coupled via bus connectors and expansion
slots to one or more expansion modules which implement the
transmitter and receiver circuitry and other interface circuitry
necessary to interface the gateway to the satellite, HFC, POTS or
DSL media or any other media such as the power lines or wireless
local loops which may be developed in the future. Modules are shown
for currently existing technologies only, but newer upstream and
downstream media are sure to follow, and the genus of the invention
includes expansion modules of whatever type are needed to interface
to these newer media.
[0262] The ADSL modem module 378 may be any conventional ADSL modem
182 or SDSL modem or any other modem to interface to any type of
digital subscriber line local loop which can be digitally
controlled by the host 128. It will include any connectors and
isolation circuitry 204 needed to connect to the DSL CO trunk
line.
[0263] The FAX/Data Modem Module 380 can be any conventional
FAX/Data modem or simple data modem for coupling via suitable
connectors and isolation circuitry 205 to extension phone lines 354
within the customer premises as well as DSL CO trunk lines 58 and
which can be digitally controlled by the host 128.
[0264] The IP & PBX telephony module 372 can be any known or
future developed "PBX on a card" including one or more expansion
cards which give a conventional personal computer host 128 running
any operating system PBX capabilities and which can be digitally
controlled by the host 128. It can include any needed additional
known circuitry and software needed to implement IP telephony
functions.
[0265] A DOCSIS modem module can be any known or future developed
cable modem that conforms to the DOCSIS standard or any new
standard for modems that allow high speed data transfers from a
customer premises to a headend cable modem and/or the internet over
a CATV HFC cable plant, and which can be digitally controlled by
the host 128.
[0266] An HFC digital video module 388 can be any digital video
receiver which can be digitally controlled by the host 128 and is
compatible with reception of digitized compressed video data
transmitted over HFC. In the system of FIG. 4A, for example, the
HFC digital video module 388 would typically include tuner 108, an
A/D converter included in matrix 130, QAM demodulator 146,
transport demultiplexer 148 and conditional access circuit 126 to
communicate with the shared IP video process 158 running in
software on the host. It may also include the upstream and
downstream combiner and isolation circuits 90 and 98 although this
combiner and isolation circuitry may be shared by all HFC interface
modules in some embodiments.
[0267] An HFC analog video module 390 can be any receiver capable
of receiving regularly scheduled analog CATV transmissions over HFC
which can digitize and compress the data for transmission over the
LAN and which can be digitally controlled by the host 128. In the
exemplary embodiment of FIGS. 4A and 4B, the module 390 typically
would include tuner 100, an A/D converter from matrix 130, video
demodulator 138, video decoder 114 and MPEG encoder 147. It may
also include the upstream and downstream combiner and isolation
circuits 90 and 98 although this combiner and isolation circuitry
may be shared by all HFC interface modules in some embodiments.
[0268] In some species within the genus of the invention, all HFC
interface modules such as 386, 388 and 390 may be combined into one
HFC interface module. Likewise for all expansion modules that
interface to the PSTN and extension phone lines or all modules that
interface with the satellite dish.
[0269] A satellite digital video-on-demand module 392 can be any
satellite receiver which can be digitally controlled by the host
128 to tune in and receive a specifically requested compressed
digital video-on-demand broadcast from a satellite. In the
embodiment of FIGS. 4A and 4B, it includes tuner 180, QPSK
demodulator 220, transport demultiplexer 184 and conditional access
circuit 186.
[0270] A satellite analog video video module 394 can be any
coventional C-band satellite receiver modified to receive tuning
commands digitally from the host 128 and modified to digitize and
compress the video program for distribution on a LAN. In the
embodiment of FIGS. 4A and 4B, it would include tuner 314, A/D
converter 316, video demodulator 320, video decoder 324 and MPEG
encoder 326.
[0271] A satellite DirectPC module 396 can be any conventional
DirectPC receiver or any equivalent receiver for receiving IP
packetized data transmitted from a satellite capable of being
digitally controlled by a host computer and send the recovered IP
packets to a routing process being run by the host. In the
embodiment of FIGS. 4A and 4B, it would include tuner 302 and QPSK
demodulator 304.
[0272] A satellite DirecTV module 398 can be any conventional
DirecTV receiver or equivalent digital satellite TV broadcast
receiver which can receive regularly-scheduled, compressed, digital
TV broadcasts from a satellite but modified to be controlled
digitally by the host 128 to tune to a requested broadcast channel.
In the embodiment of FIGS. 4A and 4B, this module would include
tuner 344, QAM demodulator 346, transport demultiplexer 350,
optionally transcoder 352 and conditional access circuit 354.
[0273] A terrestial analog NTSC or PAL or SECAM module 400 can be
any receiver capable of being digitally tuned by the host computer
which can receive regularly scheduled analog TV broadcasts via an
antenna and digitize and compress them for distribution over a LAN.
In the embodiment of FIGS. 4A and 4B, it would include tuner 332,
A/D converter 334, video demodulator 336, video decoder 340 and
MPEG encoder 342.
[0274] Any of the modules defined above which recover or generate
digital data for transmission on the LAN can optionally include a
transcoder to translate the original bit rate to a lower bit rate
where needed because of network loading. Likewise, any module that
recovers digital data that encodes copyrighted materials such as
video or audio programs may include a C5 standard encryption
circuit to re-encode the digital data before transmission on the
LAN to prevent perfect, unauthorized digital copies which could
happen if the digital data were to be transmitted in the clear.
[0275] Although the invention has been disclosed in terms of the
preferred and alternative embodiments disclosed herein, those
skilled in the art will appreciate possible alternative embodiments
and other modifications to the teachings disclosed herein which do
not depart from the spirit and scope of the invention. All such
alternative embodiments and other modifications are intended to be
included within the scope of the claims appended hereto.
* * * * *
References