U.S. patent application number 10/131300 was filed with the patent office on 2002-08-29 for access network over a shared medium.
Invention is credited to Hansson, Allan, Tonnby, Ingmar.
Application Number | 20020118676 10/131300 |
Document ID | / |
Family ID | 26662665 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020118676 |
Kind Code |
A1 |
Tonnby, Ingmar ; et
al. |
August 29, 2002 |
Access network over a shared medium
Abstract
A method for providing access to sources of at least one
telephone network and at least one IP based network over a TV
distribution network. The method uses the IP protocols as an
internal multiplexing technique and transport mechanism. The IP
handling takes places between a TV IP network terminal, connected
to a user end of the TV distribution network, via an IP access
server, connected to a TV transmitter end of the TV distribution
network, to a telephony server and a router, respectively. The
method and system allows for simultaneous datacom and telephone
traffic within one network terminal, within the TV distribution
network, or access to connected service providers of telephone and
IP based networks.
Inventors: |
Tonnby, Ingmar; (Stockholm,
SE) ; Hansson, Allan; (Stockholm, SE) |
Correspondence
Address: |
Ronald L. Grudziecki
BURNS, DOANE, SWECKER & MATHIS, L.L.P.
P.O. Box 1404
Alexandria
VA
22313-1404
US
|
Family ID: |
26662665 |
Appl. No.: |
10/131300 |
Filed: |
April 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10131300 |
Apr 24, 2002 |
|
|
|
08868653 |
Jun 4, 1997 |
|
|
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Current U.S.
Class: |
370/352 ;
348/552; 370/401; 370/465; 370/480; 375/E7.02 |
Current CPC
Class: |
H04M 3/436 20130101;
H04L 12/5692 20130101; H04M 7/1215 20130101; H04Q 11/0457 20130101;
H04Q 2213/13199 20130101; H04Q 2213/13093 20130101; H04M 3/428
20130101; H04L 12/2856 20130101; H04Q 2213/13389 20130101; H04L
12/2863 20130101; H04M 2207/203 20130101; H04M 11/06 20130101; H04Q
2213/13204 20130101; H04Q 3/72 20130101; H04N 21/238 20130101; H04L
12/2865 20130101; H04M 2242/22 20130101; H04Q 2213/13298 20130101;
H04M 3/42289 20130101; H04M 3/54 20130101; H04M 3/4285 20130101;
H04Q 2213/13106 20130101; H04Q 2213/13209 20130101; H04M 3/42102
20130101; H04M 3/382 20130101 |
Class at
Publication: |
370/352 ;
370/401; 370/465; 370/480; 348/552 |
International
Class: |
H04L 012/66; H04L
012/28; H04L 012/56; H04J 003/16; H04J 003/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 4, 1996 |
SE |
9602212-4 |
Nov 29, 1996 |
SE |
9604409-4 |
Claims
1. A method to provide access to services of a multitude of
different communication service networks over a TV distribution
network, comprising the step of using Internet Protocols (IP) as a
common internal multiplexing and transport mechanism in an
interaction channel of the TV distribution network, the interaction
channel supporting bi-directional communication via the TV
distribution network with the multitude of different communication
service networks simultaneously with TV broadcasting in the TV
distribution network.
2. The method of claim 1, wherein the multitude of communication
service networks comprises at least one telephony service
network.
3. The method of claim 1, wherein the multitude of communication
service networks comprises at least one IP based network.
4. The method of claim 2, further comprising the step of providing
IP protocol handling in a network terminal connected to a user end
of the TV distribution network.
5. The method of claim 4, further comprising the step of carrying
out access to the telephony service network via a telephony server
connected to an IP access server, which in turn is connected to a
TV transmitter end of the TV distribution network, which is common
for a suitable set of users.
6. The method of claim 4, further comprising the step of carrying
out access to the IP based network via a router connected to an IP
access server, which in turn is connected to a TV transmitter end
of the TV distribution network, which is common for a suitable set
of users.
7. The method of claim 5, further comprising the step of
associating in at least one of the telephony server and the router,
an external address with an IP address in the TV distribution
network.
8. The method of claim 4, further comprising the step of allowing
simultaneous telephony and data communication sessions on the same
network terminal.
9. The method of claim 4, further comprising the step of providing
access simultaneously for more than one telephony session on the
same network terminal.
10. The method of claim 9, wherein the simultaneous telephony
sessions on the same network terminal use different telephony
service networks.
11. The method of claim 4, further comprising the step of providing
access simultaneously for more than one datacom session on the same
network terminal.
12. The method of claim 11, wherein the simultaneous datacom
sessions on the same network terminal are given access to different
IP based networks.
13. The method of claim 4, wherein at least one addressable unit
related to one network terminal is associated with more than one
external address.
14. The method of claim 4, wherein at least one external address is
associated with more than one addressable unit related to the same
network terminal.
15. The method of claim 4, further comprising the step of
supporting internal telephone calls between different telephony
devices connected to the same network terminal.
16. The method of claim 4, further comprising the step of
supporting internal datacom sessions between different computer
devices connected to the same network terminal.
17. The method of claim 4, further comprising the step of providing
users of the same network terminal with access to several different
telephony service networks.
18. The method of claim 17, further comprising the step of
selecting required telephony service network on a per call
basis.
19. The method of claim 4, further comprising the step of providing
users of the same network terminal with access to several different
IP based networks.
20. The method of claim 19, further comprising the step of
selecting a required IP based network on a per session basis.
21. The method of claim 1, further comprising the step of
supporting internal telephone calls between different telephony
devices connected to the same TV distribution network.
22. The method of claim 1, further comprising the step of
supporting internal datacom sessions between different computer
devices connected to the same TV distribution network.
23. A network terminal for providing access to services of a
multitude of different communication service networks over a TV
distribution network, wherein the network terminal is located at a
user end of the TV distribution network and comprises means for
using Internet Protocols (IP) as a common internal multiplexing and
transport mechanism in an interaction channel of the TV
distribution network, and at least one interface for communicating
with a respective one of the multitude of different communication
service networks, wherein the interaction channel supports
bi-directional communication via the TV distribution network
between the network terminal and the multitude of different
communication service networks simultaneously with TV broadcasting
in the TV distribution network.
24. The network terminal of claim 23, wherein the multitude of
communication service networks includes at least one telephony
service network.
25. The network terminal of claim 23, wherein the multitude of
communication service networks includes at least one IP based
network.
26. The network terminal of claim 25, wherein the network terminal
comprises at least one interface to a terminal unit.
27. The network terminal of claim 26, further comprising at least
one telephony interface supporting communication for access to the
telephony network.
28. The network terminal of claim 26, further comprising at least
one PC/LAN interface supporting communication for access to the IP
based network.
29. The network terminal of claim 25, further comprising
applications for telephony, IP traffic and management of the
network terminal configuration.
30. The network terminal of claim 29, further comprising means for
communication with the management application of the network
terminal, for enabling modification of a configuration of the
network terminal.
31. A telephony server for providing access to services of at least
one telephony network over a TV distribution network, comprising
means for connecting the telephony server to an Internet Protocol
(IP) access server, which in turn is connected to a TV transmitter
end of the TV distribution network, and means for using the IP
protocols as a common internal multiplexing and transport mechanism
in an interaction channel of the TV distribution network, and means
for associating a telephone number with a terminal at a user end of
the TV distribution network, wherein the interaction channel
supports bi-directional communication via the TV distribution
network between the terminal and the at least one telephony network
simultaneously with TV broadcasting in the TV distribution
network.
32. The telephony server of claim 31, wherein the telephony server
has access to more than one telephony network.
33. The telephony server of claim 31, wherein the telephony server
comprises a telephony application.
34. The telephony server of claim 31, further comprising means for
associating an external telephony address with an internal IP
address.
35. The telephony server of claim 31, further comprising an
application for management of the telephony server and means for
communication with the management application, for enabling
modification of a configuration of the telephony server.
36. A router for providing access to services of at least one
Internet Protocol (IP) based network over a TV distribution
network, comprising means for connecting the router to an IP access
server, which in turn is connected to a TV transmitter end of the
TV distribution network, and means for using the IP protocols as a
common internal multiplexing and transport mechanism in an
interaction channel of the TV distribution network, wherein the
interaction channel supports bi-directional communication via the
TV distribution network between a terminal at a user end of the TV
distribution network and the at least one IP based network
simultaneously with TV broadcasting in the TV distribution
network.
37. The router of claim 36, wherein the router has access to more
than IP based network.
38. The router of claim 37, wherein the router has an IP
application which communicates with the IP based networks.
39. The router of claim 36, further comprising means for
associating an external IP address with an internal IP address.
40. The router of claim 36, further comprising an application for
management of the router and means for communication with the
management application, for enabling modification of the
configuration of router.
41. A network node for providing access to services of at least one
Internet Protocol (IP) based network and of at least one telephony
service network, comprising an IP access server, a router connected
to the IP access server and with IP interfaces for connection to a
respective one of the IP based networks, a telephony server
connected to the IP access server and with a number of telephony
interfaces for connection to respective ones of the telephony
service networks, the IP protocol being used as a common internal
multiplexing and transport mechanism, whereby a user terminal in
communication with the network node is able to communicate using IP
with the at least one IP based network and with the at least one
telephony service network.
42. An arrangement for providing access to services of an Internet
Protocol (IP) based network over a TV distribution network,
comprising a network terminal located at a user end of the TV
distribution network, a telephony server connected to an IP access
server, which in turn is connected to a TV transmitter end of the
TV distribution network, and a router connected to the IP access
server, using the IP protocols as a common internal multiplexing
and transport mechanism in an interaction channel of the TV
distribution network, wherein the interaction channel supports
bi-directional communication via the TV distribution network
between the network terminal and the IP based network
simultaneously with TV broadcasting in the TV distribution
network.
43. An access network comprising a number of network terminals and
a network node, the network node having a telephony network
interface and an Internet Protocol (IP) access server, a router
connected to the IP access server and having an IP network
interface, a telephony server connected to the IP access server and
to the telephony network interface, the number of network terminals
being connected to the IP access server at TV distribution network
interfaces provided in the IP access server networks, wherein the
TV distribution network interfaces support bi-directional IP based
communication between the network terminals and at least one IP
based network and at least one telephony service network
simultaneously with TV broadcasting in a TV distribution network to
which the TV distribution network interfaces are connected, the IP
protocol being used as a common internal multiplexing and transport
mechanism in an interaction channel of the TV distribution network,
whereby the network terminals are able to communicate using IP with
the at least one IP based network and telephony service network via
the TV distribution network interfaces.
44. The access network of claim 43, wherein the router has several
IP network interfaces, each one of which is connected to a
respective one of several IP networks.
45. The access network of claim 43, wherein the telephony server
has several telephony network interfaces, each one of which is
connected to a respective one of several telephony service
networks.
46. A network terminal comprising: at least one local area network
(LAN) interface; a plurality of telephone interfaces; a TV
interface compatible with a TV distribution network; a digital
stream service (DSS), wherein the DSS provides a bi-directional
interaction channel over the TV distribution network through which
Internet protocol (IP) is used as the common internal multiplexing
and transport mechanism and IP packets are transmitted and
received; and an IP multiplexer/demultiplexer, which transfers IP
packets between the DSS and one of the at least one LAN interface
and the plurality of telephone interfaces, wherein IP packets
corresponding to a telephone call are routed to one of the
plurality of telephone interfaces depending on the origin of the
telephone call.
47. The network terminal of claim 91, wherein the at least a
portion of the plurality of telephone interfaces are associated
with a same telephone number.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation fo application Ser. No.
08/868,653, filed on Jun. 4, 1997, the entire disclosure of which
is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to telecommunication in
general and to voice and data communication. In particular the
invention relates to access to telephony networks and Internet
protocol (IP) based networks over a shared physical medium, such as
a TV distribution network.
BACKGROUND
[0003] Traditional cable TV (CATV) networks are analogue and
unidirectional networks for distribution of TV programs to many
users. This is performed via a branched distribution network
comprising cascaded amplifiers. The cable will constitute a shared
physical medium, where the headend provides the analogue signals
and the user end terminals tap the signals. A single cable TV
headend may serve over 100000 users within a distance of up to 15
km via one single trunk.
[0004] Upgraded CATV networks support bi-directional communication,
and thus the amplifiers also have to support bi-directional
communication. The cable will then behave like a closed ether, the
frequency spectrum of which is available for communication between
the head end and the users. The network is normally asymmetric in
transfer capabilities, a few Mb/s available in the upstream
channels and 10-50 Mb/s in the downstream channels, beside a number
of TV channels. The number of users is so large that non-compressed
voice may only be provided to a small fraction of users.
[0005] Hybrid-fibre coax network, where parts of the coax network
are replaced by networks with optical fibre, have fewer users,
normally a couple of thousand. The available bandwidth is shared by
much fewer users and is sufficient to provide two-way communication
for all users. An even more upgraded type of network solution is
according to the Regional Hub/Passive Coaxial Network Architecture.
The fibre node in such a configuration typically serves 200-500
users.
[0006] Recently, a rapid development has taken place in order to
extend the range of services which can be supported by cable TV
network. The main issue is related to support of IP access and
telephone access by using two-way channels over a cable TV network.
An IEEE group 802.14 is developing a standard for the physical
layer and a MAC (Medium Access Control) protocol for CATV networks.
It will support both connectionless and connection-oriented
services. Stream services, such as constant bit rate (CBR),
variable bit rate (VBR) and available bit rate (ABR) will be
handled. The network should be used to support unicast, multicast
and broadcast services. It will also support ATM (Asynchronous
Transfer Mode). Generally, the upstream bandwidth is much lower
than the downstream bandwidth.
[0007] One example of a possible protocol stack is one using the
IEEE protocols, which uses Medium Access Control (MAC) layers,
according to IEEE 802.3 and 802.14 (in particular the Draft
Supplement to IEEE Std 802.14, 802.14MACN 1.1, Dec. 31, 1996),
above which there is a Logical Link Control (LLC) layer, according
to IEEE 802, which at the end user and the IP access server
supports the Internet Protocol (IP). The IEEE protocols can be part
of a solution to provide access to telephony networks, e.g. PSTN
(Public Switched Telephone Network). A control protocol, as well as
the user data are carried on top of the link layer.
[0008] Other telephony access approaches over a CATV network
allocate a channel, allowing for a two-way, e.g. 64 kb/s, stream
for each call. Also such solutions are dependent on the development
of control signalling handling solutions.
[0009] An interaction channel is provided to digital video
broadcasting (DVB) systems based on digital enhanced cordless
telecommunications (DECT). A European draft specification of such a
system is known in the art, e.g. through "Draft specification of
DVB Interaction Channel based on DECT", DVB-RC-165 rev 7, version
4.0, Mar. 27, 1997. In this specification a packet distributing
service point-to-point is available together with the DVB. The DECT
specification also provides 32 kb/s channels for telephony. In this
specification a protocol stack model is presented, which in the
bottom has protocols for modulation, channel coding, frequency
range, filtering, equalisation and power. On top of this, protocols
for the access mechanism and packet structure is provided, all
connected to the actual network. The network independent protocols
are then placed on top of this.
[0010] A new technique that for simultaneously an Internet session
and a telephony session over the same telephone access line
includes a telephone doubler arrangementphone doubler described in
FIG. 10 below and in Swedish Patent Application No. 9602212-4.
[0011] The telephone doubler arrangement permits a user which is
connected to an analogue telephone network to access an IP-based
communication service and still be able to receive and answer
incoming calls, and to place outgoing calls, while simultaneously
surfing the Internet.
[0012] In FIG. 10 the telephone doubler arrangement 101 is shown to
be connected to PSTN 102 and to Internet 103. At the user side a
modem 104 is connected to PSTN 102, to a standard analogue
telephone 105 and to a PC 106. The telephone doubler arrangement
101 comprises a modem pool 107 connected to PSTN 102, to Internet
103 and to a telephony server 109. The telephony server 109 is
connected to PSTN 102.
[0013] When a user A is connected to Internet 103 via a dialed up
PSTN connection to the modem pool 107 the telephone 105 cannot be
used. On his/her PC the user can still communicate with other PSTN
users by using the connectivity and multiplexing capabilities of
IP. The dialed up line can carry a multiplexed stream of IP
packages of: (a) an Internet session and (b) a telephony call.
Speech carrying IP packages are routed to/from the telephony server
109 to PSTN. Telephony control signals are exchanged between the
telephony server 109 and a telephony application 110 which runs on
the PC. If the PC has audio capabilities, symbolized by a headset
111 comprising earphones and a microphone, a user A can be engaged
in speech conversations with other users connected to the PSTN or
ISDN. The user has got a new, soft phone on the PC 106.
[0014] Another new technique that allows for simultaneously an
Internet session and a telephony session over the same telephone
access line includes makes use of the telephone doubler principle
described above complemented, at the user end, with an IP modem 112
as shown in FIG. 11 and in Swedish Patent Application No.
9604409-4. IP functionality, such as provided by the PC 106 in FIG.
10, has been integrated in the modem 112 and therefore the modem is
referred to as an IP modem.
[0015] This arrangement makes possible a dialed up connection,
using a standard analog telephone, or a telephony application on a
PC, while simultaneously an Internet user is engaged in an Internet
session over a PC connected to the same IP modem.
[0016] The arrangement shown in FIG. 11 is similar to that of FIG.
10. A telephone doubler arrangement 101 is connected to PSTN and
Internet and comprises the same units as in FIG. 10.
[0017] Over a first IP link 113 between the IP modem and Internet
103 IP packets containing information relating to an Internet
session are transported. Part of this link comprises a subscriber
line 114 extending between the IP modem and PSTN. Over a second IP
link 115 IP packets carrying digitized, compressed speech are
transported to/from the telephony server and the modem pool. The
telephony server creates a dynamic relation between the IP address
of the IP modem and the telephone number of user A. Using the call
forwarding service in PSTN incoming calls to user A are redirected
to the telephony server.
[0018] The arrangement will allow user A to take and to place
telephone calls using the ordinary telephone while there is an
ongoing Internet session on the personal computer. Also a "soft
phone" like the one in Appl. No. 9602212-4 cited above is provided.
Since the modem has IP capabilities it will be possible to
communicate with other devices, such as additional equipment can be
connected to it, such as a private LAN, an electricity consumption
meter and similar devices, over a home network.
[0019] The IP modem is shown in FIG. 12 and comprises a subscriber
line interface 116, one or more telephone interfaces 117,118, at
least one PC interface 119 and, optionally, a LAN interface 120.
There is also an IP multiplexor/demultiplexor 121 and a controller
122. An optional application 123 can run in the IP modem, such as
for example an e-mail poller for polling electronic mail-boxes of
user A. The IP multiplexor/demultiplexor routes IP packets from the
subscriber line interface to their destinations; the PC, the
telephone or the LAN. The controller provides control over the
functionalities of the IP modem.
[0020] The Swedish applications cited above both provide telephony
access and IP traffic can be superimposed the telephony access.
However, both solutions are limited to one service provider of
telephone networks or IP based networks. The solutions are also
limited to a PSTN network as access network.
SUMMARY
[0021] One object of the present invention is to provide access to
services of at least one telephony network and at least one IP
based network over a TV distribution network, a shared medium,
which is enhanced to provide logical two-way links.
[0022] Another object of the present invention is to provide
simultaneous telephony and IP access and to provide more than one
simultaneous telephony connection to one particular customer.
[0023] Still another object of the present invention is to allow
different users of the same network or a single user to relate to
different service providers of the same service, e.g. telephony or
Internet.
[0024] Internal calls between different telephony devices of the
same network terminal or connected to the same TV distribution
network are also to be supported.
[0025] The above objects are provided by a method and devices
according to the present invention as it is defined in the enclosed
claims.
[0026] According to the invention a method is provided, which
provides access to at least one telephony network, using a TV
distribution network with an interaction channel, supporting
bi-directional communication, as a transmission medium
simultaneously to TV broadcasting. The method uses IP as an
internal multiplexing technique.
[0027] Moreover, according to the invention a TV Internet Protocol
Network Terminal, hereafter called "NT", which functions as an end
user network terminal, i.e. a receiver end, of the TV distribution
network, is provided with interfaces for different terminal units,
e.g. telephony interfaces and computer or LAN interfaces. The
LAN/PC interface supports exchange of IP packets and the telephony
interfaces are enhanced with capabilities to detect control signals
from the phone and to generate control signals to the phone as well
as to digitise speech and decode digital information into speech.
The NT also contains functionality to support services, e.g.
telephony. It also provides communication with external
applications.
[0028] The invention also provides a telephony server, which has
connections to at least one telephony network and which comprises
means for associating a certain telephone number with a certain NT
and means assisting in using IP as a multiplexing technique. The
telephony server also provides functionality to support telephony,
and comprises means to interface one or more telephony
networks.
[0029] Similarly, the invention also provides a router, which has
access to at least one IP based network and which comprises means
for associating a certain external IP address with a certain NT and
means assisting in using IP as a multiplexing technique.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The invention and its merits will be described in connection
with the accompanying drawings, in which
[0031] FIG. 1 is a block diagram of entities involved in the access
handling via a TV distribution network in accordance with the
invention,
[0032] FIG. 2 is a functional block diagram of the network terminal
in accordance with the invention,
[0033] FIG. 3a is a block diagram of an example of a part of a
protocol stack, which may be used for the external port in the NT
in accordance with the invention,
[0034] FIG. 3b is a block diagram illustrating how the access
network handles the telephony application,
[0035] FIG. 3c is a block diagram illustrating how the access
network handles the IP application,
[0036] FIG. 4 is a block diagram of entities involved in the access
handling via a TV distribution network in accordance with the
invention, with two telephones connected to the same NT.
[0037] FIG. 5 is a block diagram of entities involved in the
telephony access handling via a TV distribution network in
accordance with the invention, illustrating telephone communication
between a telephony application at a computer and a normal
telephone.
[0038] FIG. 6 is a block diagram of entities involved in the
telephony access handling via a TV distribution network in
accordance with the invention, illustrating telephone communication
between a telephone and a telephony application at a computer via
Internet.
[0039] FIG. 7 is a block diagram of entities involved in the access
handling via a TV distribution network in accordance with the
invention, where several service providers are present,
[0040] FIG. 8 is a block diagram of entities involved in the
telephony access handling via a TV distribution network in
accordance with the invention, illustrating internal communication
between two telephones or between a telephone and a telephony
application on a computer, connected to the same NT,
[0041] FIG. 9 is a block diagram of entities involved in the
telephony access handling via a TV distribution network in
accordance with the invention, illustrating internal communication
between two telephones connected to the same TV distribution
network,
[0042] FIG. 10 shows a block diagram of a related art "phone
doubler" technique, as presented in reference [1],
[0043] FIG. 11 shows a block diagram of a related art "IP modem"
technique, as presented in reference [2], and
[0044] FIG. 12 shows the functional blocks of the IP modem, shown
in FIG. 11.
DETAILED DESCRIPTION
[0045] In FIG. 1 a user A has a telephone 1, a personal computer 2
and a television set 3. The television set 3 is connected via a set
top box (STB) 4 to a NT 5 in accordance with the invention. The NT
5 includes a telephony interface 6 and a computer interface 7, by
which the telephone 1 and the personal computer 2, respectively,
are connected. The NT 5 constitutes the user end terminal, i.e. a
TV receiver end, of a TV distribution network 8. It communicates
with a TV transmitter end 9 via the TV distribution network 8.
[0046] The TV transmitter end 9 is conventionally supplied with TV
programs from various sources, one of which is shown at 10. The TV
programs 10 are distributed from the TV transmitter end 9 to the
different end users via the TV distribution network 8 according to
conventional methods. The NT 5 is transparent regarding the
frequency channels used for the TV broadcasting and these
frequencies are passed unaltered to the STB 4, which carries out
the conventional procedures for supplying the TV programs to the TV
set 3. The information flow for the TV broadcasting is indicated by
the dashdot line 11 in FIG. 1.
[0047] The distribution of TV programs is not affected by the use
of the present invention, and this will therefore not be discussed
in full detail. The only feature request of the TV distribution
network 8 is that it supplies a link service, which receives
IP-packets and delivers them safely to the intended destination
point. For example, in a conventional CATV network, the TV
transmitter end 9 is e.g. constituted by a CATV headend. The TV
transmitter end 9 is thus only characterised by being a point in
the network which is common for a suitable set of users. In more
sophisticated CATV network configurations, see e.g. Draft
Supplement to IEEE 802.14, "Physical layer Specification for HFC
CATV Networks", 802.14PHYN.1.0, Feb. 7, 1997, fibre hubs, regional
hubs etc. may thus be the TV transmitter end 9 of the present
invention.
[0048] An attractive scheme for providing an interaction channel in
a TV distribution network 8 is presented by "Draft specification of
DVB Interaction Channel based on DECT", DVB-RC-165 rev 7, vers.
4.0, Mar. 27, 1997. In this scheme two channels are established
between the service provider and the user. A unidirectional
broadband broadcast channel including video, audio and data
corresponds to the conventional cable TV service. A bi-directional
interaction channel is also established between the service
provider and the user for interaction purposes and is formed by a
forward interaction path and a return interaction path.
[0049] The TV transmitter end 9 Is also permanently connected to an
IP access server 12 via e.g. a LAN 13 with a link protocol. The IP
access server 12 is connected to a router 24 and a telephony server
15. The router 24 has in a conventional manner access to Internet
14. The telephony server 15 is in turn connected to PSTN 16 and
provides the telephony service to users of the TV distribution
network 8. Another user B 17 has a telephone connected to the PSTN
16 via a subscriber line 18.
[0050] The IEEE set of LAN related protocols gives an opportunity
to extend the link service between the NT:s 5 and the IP access
server 12. By the means of a bridging protocol 42 (FIG. 3a)
according to IEEE 802.1, the link protocol, e.g. LLC 41 (FIG. 3a)
can operate over different domains with different physical and MAC
protocols, e.g. the cable TV MAC protocol according to IEEE 802.14
between an NT 5 and a TV transmitter end 9 and Ethernet (IEEE
802.3) between the TV transmitter end 9 and the IP access server
12. This means that the bridging protocol 42 (FIG. 3a) takes care
of the task of changing medium during the transmission of packets
from/to the IP access server 12 to/from the right NT 5.
[0051] FIG. 3a shows an example of a part of a possible protocol
stack of the external port in the NT 5. The external coaxial port
stack has the Analogue bearer 45 as the lowest protocol layer. On
top of this, a Physical layer 44 and above that a Medium Access
Control layer 43, and a bridging protocol 42. On top of the
bridging layer is a LLC layer 41, and on top of that an IP layer 40
which transmits packets between the NT 5 and the IP access server
12 ports. The service of the LLC 41 is to transfer packets point to
point between NT's 5 and the IP access server 12.
[0052] The telephony server 15 comprises a telephony application
50a (FIG. 3b). This telephony application 50a is intended to
communicate with a telephony application 50c (FIG. 3b) in the NT 5
and create a relation (call) between instances in both entities,
i.e. the telephony applications 50a, 50c handle the relations
between telephone numbers or equivalent and local addresses and
port numbers for the telephony applications. The telephony
applications 50a, 50c also handle the telephony signalling, i.e.
handle the service specific protocols, e.g. control protocols for
telephony.
[0053] More in detail, FIG. 3b illustrates how the access network
handles the telephony application. The basic principle is that the
internal communication, to/from the telephony server 15 from/to the
NT 5, is performed by IP. Accordingly, the system provides an IP
domain 40, in which several units communicate by IP. It may also be
noted that the entire communication takes place on a level above
the TV transmitter end 9.
[0054] A telephony application 50a in the telephony server 15
communicates with a telephony service network (not shown). This is
preferably done using conventional protocols for control signalling
53a (e.g. V5.2) and speech transferring 52a. The telephony
application 50a in the telephony server 15 also communicates with a
telephony application 50c in the NT:s 5 by an internal application
specific protocol, which e.g. can be V5.2 or another protocol for
telephony. In this communication, speech is controlled by a speech
handling protocol 52b, 52c and a UDP (User Datagram Protocol) 54b,
54c in both the telephony server 15 and the NT:s 5 and the
resulting packages are communicated by the IP domain 40. In
parallel, control signalling is handled by a control protocol 53b,
53c and a TDP (Transmission Control Protocol) 55b, 55c above the IP
communication layer 40.
[0055] The telephony application 50c in the NT 5 is in its turn
communicating with a connected telephone 1 and users using them,
using an analogue traditional protocol for telephony 51, via e.g.
an analogue telephone interface. Also here speech and control
signalling are separated, the speech using a UDP 54d and a CODEC
56, while the control signalling is using a TCP 55d and control
protocol 53d. There are also possibilities to handle the
communication between the telephone application 50c and the
respective interfaces in NT:s 5 in other ways than with IP 40, but
IP 40 is presently considered as the most preferable solution.
[0056] The IP router 24 (FIG. 1) comprises an IP application. This
IP application is intended to handle the relations between external
IP addresses or equivalent and local addresses and port numbers for
the IP applications.
[0057] FIG. 3c illustrates how the access network works with the IP
application 60a, 60b. In this example, the address mapping between
external and internal addresses (described further below) in the
case of IP communication can be solved by e.g. using tunnelling,
which by itself is known in the art. There are several known
tunnelling protocols 61a, 61b, and the procedure to establish a
tunnel between the router 24 and the PC 2 and will therefore not be
further described in detail. In this case, however, a tunnel is a
mechanism to convey IP packets between two points by means of IP as
a transport protocol 40. IP packets are thus conveyed as data in
other IP packets. The address spaces are different between the two
layers of IP. Generally, the lower IP layer 40 is associated with
internal IP addresses, while the upper IP layer 60a, 60b is
associated with external IP addresses. In cases where the
communication is to be terminated in the NT 5, there are also (not
shown) corresponding tunnelling protocols and IP available. This
may be useful, for instance, when a user via an analogue telephone
wants to have access to the Internet phone capabilities.
[0058] Address Mapping and Routing
[0059] Address mapping plays an important role in the present
invention. The arrangement with several different service providers
of each type of service network give rise to several address
spaces, which therefore are not possible to use as internal
addresses.
[0060] An IP address is a reference to an interface and a port
behind that interface.
[0061] Usually, a port designates an application.
[0062] A network terminal 5 has an internal IP address (internal
refers to the access network, i.e. the IP address is not known
outside of the access network). Further, a number of ports, each
one attached to an application (residing in the NT), which can be
reached over IP, are defined for an NT 5. E.g., the telephony
application 50c is addressed by the IP address of the NT 5, and a
unique port number. The different accesses, which supports a single
device (e.g. a serial port or an analogue telephone access) are
seen as applications, and are thus addressed by port numbers.
Devices connected to a LAN have their own internal IP address. If
they want to communicate over an external IP network 14, they have
to have an external IP address as well.
[0063] A telephony number, which is associated to a subscription of
a telephony service, is associated to one or more devices (attached
to an NT 5) with capabilities to handle telephony. Such devices can
be e.g. analogue or digital telephones.
[0064] Within the access network, e.g. in case of an incoming call
to this destination, it is sufficient to be able to address the NT
5 and the telephone application 50c. This is done by mapping the
external telephone number (or a representation of it) on the
internal address of the NT 5, and the port number of the telephony
application 50c. By information carried over the application
protocol, the telephony application 50c knows the destination of
the call. The telephony application 50c holds information of which
telephone interfaces are involved in the destination.
[0065] The telephony application 50c in an NT 5 communicates with
the telephony application 50a in the telephony server 15, which has
a similar address (IP address of the telephony server 15 including
a port address. The telephony application 50a in the telephony
server can in its turn address the proper interface of a wanted
telephony network 16.
[0066] In case of communication with an external IP network 14, a
tunnelling technique can be used. There are several ways to handle
this. We assume that the tunnel extends between the PC 2 and the
router 24, which handles the interfaces to the external networks
14. All packets travelling a tunnel towards the router 24 are
destinated to the same external IP network 14. A PC 2 has an
internal IP address and an external IP address.
[0067] In that case, an IP packet, which arrives to the router 24
from an external IP network 14, and which is addressed to an
application on the PC 2 (by an external IP address with a port
number), is handled in the following way. The external IP address
is mapped on the internal IP address of the PC 2, including a port
number referring to an application which handles the tunnelling
protocol. The IP packet is then put in a new IP envelope with the
internal IP address, and routed over the access network to to the
destination PC 2.
[0068] An IP packet, which is sent from a PC 2 to an external
address, is tunnelled in the same way by an internal IP address,
which points out an application handling the tunnelling protocols.
The tunnel identity points out which interface the packet is aimed
for.
[0069] Before the NT 5 is used for traffic purposes it has to be
configured, e.g. in order to support the address mapping. The NT is
supplied with an internal address of the router 24 and/or telephony
server 15 and with data related to the requested use of the access
possibilities, i.e. the NT configuration, Such configuration
possibilities are discussed further below. When the NT 5
subsequently is installed in the TV distribution network 8, the
router 24 and the telephony server 15 has to be informed.
Accordingly, the telephony server 15 is informed about its
existence and associated internal IP addresses, the port number of
the telephony application of the NT 5 and the corresponding
telephone number or numbers or equivalent, e.g. port number in the
telephony server. Similarly, the router 24 is informed about the
internal IP address and the port number of the IP application of
the NT 5 and the corresponding external IP address or addresses. In
cases where tunnelling protocols are used, the internal address of
the PC has to be known. The NT 5 has to be configured accordingly.
E.g., a telephone number is related to a number of interfaces.
[0070] IP-Session
[0071] Data communication with an IP network is always possible
through the TV distribution network 8. The NT 5 sends IP formatted
data in the upstream channel of the TV distribution network 8 to
the IP access server 12, which directs the data to the router 24,
which in turn distributes the data towards the intended IP network,
in this embodiment at Internet 14. The router 24 and IP access
server 12 also direct data addressed to the IP address of the NT 5
in the downstream channel of the TV distribution network 8 to the
NT 5 and from there to the intended terminal. Thus, the Internet
traffic follows the path indicated by a dashed line 19 in FIG.
1.
[0072] Incoming Call
[0073] An incoming call will be handled as follows. User B 17 wants
to speak with user A 1 over the telephone and dials the telephone
number to user A. The telephony application of the telephony server
15 receives the incoming call. The telephony application in the
telephony server 15 creates a message about the incoming call. This
message is supplied with the internal IP address of the NT 5, using
the previously created relation between the destination telephone
number of the incoming call and the internal IP address, and
distributed to the IP access server 12. The IP access server 12
uses the link protocol in order to deliver it to the proper NT 5.
The NT 5 receives the data packets and deliver it to the telephony
application of the NT 5, which associates the information about the
intended receiver telephone number with a certain interface 6 (or
several). The message about the incoming call is interpreted and
user A is finally noticed about the incoming call by a conventional
ring signal on a phone initiated from the NT 5.
[0074] If user A does not answer the call, the telephony server 15
signals this to the PSTN 16 and the call is rejected, if the caller
has not given up before, and the PSTN has not already rejected the
call.
[0075] If user A answers the call by lifting the receiver at the
telephone unit, the NT 5 detects the off hook operation and sends
back a message to the telephony server 15, via the TV distribution
network 8 and the IP access server 12, for establishing the
connection towards the calling user B. In this case, the upstream
communication channels in the TV distribution network 8 are used.
The telephony server 15 forwards the answer message to PSTN 16.
When the call is completed, the telephony server 15 digitises,
compresses and packetizes B's speech and sends it over the TV
distribution network 8 using the IP protocol. The NT 5 depacketizes
the packages, decompresses the information and transforms the
digital information into speech again, which is sent to the
telephone 1 via the telephony interface 6 and an ordinary telephone
line 21. This information flow is described in detail below. Speech
originating from the user A is in a similar way digitised,
compressed and packetized in the NT 5 and is sent over the TV
distribution network 8 to the telephony server 15. The telephony
server 15 recovers the speech and sends it to user B 17 over the
ordinary PSTN network 16. This is also described in detail
below.
[0076] The information flow from user B to user A is as follows:
From user B, the speech is sent via the PSTN network 16, using any
of the conventional transmission techniques, to the telephony
server 15. This is indicated by full lines 18, 20 in FIG. 1. Here
the speech is digitised and packetized. The telephony server 15
formats the data packages according to the IP protocol and provides
the packets with an address to the NT internal IP address using the
previously stored relation between A's telephone number and A's IP
address. The information here passes as data packets on a link 13,
indicated as heavy lines in FIG. 1. The TV transmitter end 9 sends
the data packages over its downstream information channels to the
requested TV receiver end, i.e. the requested NT 5. Here, the
information travels over the TV distribution network 8, in this
example comprising DECT, indicated by a shadow line 22 in FIG. 1.
The NT 5 receives the data packages, unpacks them and sends them to
the appropriate telephony interface 6. Here the digital information
is decoded into speech information and sent to the telephone as
normal speech on a line, indicated by a full line 21 in FIG. 1. The
information flow from user B to user A is indicated by the dotted
line 23 in FIG. 1.
[0077] The information flow from user A to user B is as follows.
From user A, the speech is sent via a line 21 to the telephony
interface 6 on the NT 5, indicated by a full line in FIG. 1. Here
the speech is digitised and packetized. The NT 5 formats the data
packages according to the IP protocol, providing the data packets
with an address corresponding to the telephony server 12 internal
IP address. The data packages are sent via the upstream information
channels of the TV distribution network 8 to the TV transmitter end
9, c.f. the shadowed line 22 in FIG. 1. Here, the content in the
upstream information channels is forwarded to the IP access server
12, where the IP address of the telephony server 15 is detected and
subsequently, the data packages are forwarded to the telephony
server 15, c.f. the heavy lines 13 in FIG. 1 . The telephony server
15 receives the data packages, unpacks them, decodes the data into
speech, which is sent to the appropriate telephony port and via the
PSTN network 16 to user B 17.
[0078] When the conversation between user A and user B is finished
and A puts the receiver on hook, the NT 5 detects the on hook
condition of the telephone of user A. This on hook condition is
forwarded via the TV distribution network 8 to the telephony server
15, which terminates the connection to user B. Also, if user B
terminates the call, the telephony server 15 forwards the on hook
condition over the TV distribution network 8 to the NT 5, and the
call is terminated.
[0079] Outgoing Call
[0080] An outgoing call will be handled in a similar way. User A
wants to speak with user B over the telephone and lifts the
receiver. The NT 5 detects the off hook condition and gives a
dialling tone to the user A telephone. User A dials the telephone
number to user B. The NT 5 detects the number sequence dialled by
user A and sends it to the telephony server 15 via the TV
distribution network 8 and the IP access server 12. The telephony
server 15 places an outgoing call to the requested number on the
PSTN network 16, and sends back a confirmation message to the NT 5,
which, in turn, supplies a ring tone to the telephone of user
A.
[0081] If user B answers the call, a connection between the
telephony server 15 and user B is established over the PSTN network
16 in a conventional manner. A message about the connection is sent
by the telephony server 15 to the NT 5, the ring tone is
interrupted and the full connection is established.
[0082] If user B does not answer, user A will place the receiver on
hook. The NT 5 detects the on hook condition and sends a message to
the telephony server 15 to interrupt the call over the PSTN network
16.
[0083] The Network Terminal
[0084] In the following the NT 5 functionality will be described in
connection with FIG. 2. First of all, there is an overall control
functionality 30 for controlling the operation of the various
functionalities of the NT 5. The NT 5 further comprises at least
one LAN/PC interface 31, an IP MUX/DEMUX section 32, at least one
device feature section 33, at least one telephone interface 34, a
digital stream service 35 and a TV interface 36.
[0085] The Digital Stream Service (DSS) 35 uses the transmission
capabilities of the TV distribution network 8 (FIG. 1) to provide a
two-way digital transport capability. It uses a link protocol,
including a medium access protocol, which takes care of the
segmentation of information and delivery to the intended
destination point. Such DSS 35 may e.g. work according to the DVB
interaction channel based on DECT ("Draft specification of DVB
Interaction Channel based on DECT", DVB-RC-165 rev 7, vers. 4.0,
Mar. 27, 1997) or the specification of the IEEE 802.2 logical link
over IEEE 802.14 MAC protocol for HFC CATV networks.
[0086] The LAN/PC interface 31 supports exchange of IP packets. It
comprises a LAN or PC interface providing a serial interface
supporting IP and PPP protocol layers.
[0087] Other interfaces supporting IP is also possible, such as LAN
interfaces or the universal serial bus ("Universal Serial Bus
Specification Revision 1.0", available at
http://teleport.com/.about.USB)- .
[0088] The telephone interface 34 can be an ordinary analogue
interface, with capabilities to detect control signals from the
telephone, such as off hook, on hook, hook flash, DTMF (Dual Tone
Multi Frequency) signals etc. It may also be a digital interface,
wired or wireless, supporting corresponding signals. The telephone
interface 34 also generates ringing and acoustic signals, e.g. dial
tone. Furthermore, it also converts the analogue speech stream into
a digital stream (which may be compressed, e.g. by GSM (General
System for Mobile communication) standard or DECT), and puts it in
IP packets of proper size. Incoming IP packets, which carries
speech, are processed the reverse way, i.e. are decoded from a
digital stream into analogue speech.
[0089] The IP MUX/DEMUX 32 takes packets from the digital stream
service and delivers them to their respective interfaces
(demultiplexing). It also multiplex together the IP packets from
the different interfaces and sends them mUltiplexed to the Digital
Stream Service 35.
[0090] The TV interface 36 is a conventional interface for the TV
distribution network 8 (FIG. 1) and is not further discussed. It is
assumed that the TV channels passes the NT 5 but that it may insert
or extract TV channels.
[0091] Other Important Features
[0092] Above, the invention is discussed only regarding ordinary
phone calls. However, there are other useful features of the
invention. One such useful feature is the possibility of
simultaneous IP sessions and telephone calls over the same NT 5. A
communication capability is always available between the IP access
server 12 and the PC 2. The telephony procedure uses the same
communication medium as the IP session, the telephony data packages
are certainly mixed with the datacom traffic, but the telephone
call will not influence the session. In other words, a user of
Internet does not have to interrupt his session to make a phone
call or to receive a call from outside.
[0093] Another advantage of the telephony access according to the
present invention is illustrated by FIG. 4. In this figure, user A
has two telephones connected to the NT 5. The two phones,
designated 1a and 1b, are connected to a respective telephone
interface 6, as shown in FIG. 1. The two phones may be associated
with different phone numbers, but also with the same number. When
the NT 5 is configured it has to be decided which relations should
be available within the NT 5.
[0094] If the phones are associated with different numbers, the
procedure is very similar to the above described incoming call. A
call to the first telephone number will be directed to the phone 1a
and a call to the second telephone number will be directed to the
phone 1b. The NT 5 thus enables a multi-access possibility.
Although only two telephones of user A is shown in the figure it
will be understood that any number of telephones may be connected
in this manner.
[0095] If the different telephones are associated with the same
telephone number, the following situation is one of the possible
solutions. When a first call is initiated from an external user,
such as user B, a ringing may be initiated on both telephones. When
someone answers the call at one of the phones, the call is
connected to that particular phone, and the ringing on the other
phone is stopped. If a second call to the same phone number is
initiated from another external user, one phone is occupied but the
other one is free and the new call is alerted at the non-occupied
telephone. The NT 5 may therefore direct the new call to the
second, non-occupied phone, using a second, non-occupied telephone
interface 6.
[0096] By configuring the NT 5 in a slightly different way other
situations are possible. It is for instance possible to configure
the NT 5 in such a way that the NT 5 detects from which number the
call origins and dependent on this, call signals are sent to either
or both of the telephones 1a, 1b.
[0097] In the same way, it is possible to make an outgoing call
even if another telephone conversation is going on on one of the
phones. The second, non-occupied telephony interface will assist in
establishing the contact to the PSTN network 16.
[0098] Although only two telephones of user A is shown in the
figure it will be understood that any number of telephones may be
connected in this manner.
[0099] Similarly, one telephone connected to the NT 5 may be
associated with more than one external telephone number. This means
that e.g. if one telephone number is requested the first telephone
is addressed, if another telephone number is requested both
telephones may be addressed. It is in this way possible to
configure the functionality of the NT 5 with any combination of
addresses.
[0100] In the description of the telephony access, analogue
telephones have been assumed. Digital phones will of course work
equally well. The NT 5 will then have an interface 6 for a digital
telephone. The NT 5 then supports control signals, ringing signals
and acoustic signals, but is transferring both these signals and
the speech in digital form to the telephone.
[0101] The PC 2 may also have a telephony application 25, as
indicated in FIG. 5. The PC 2 is then normally equipped with sound
capabilities with associated audio devices. The telephony
application 25 comprises software running on the PC 2 which allows
bi-directional speech communication over the sound capability and
the audio devices. The sound capability converts the speech to
digitised and compressed audio signals, which are packetized into
IP packets. These packets are handled in the same manner as the IP
packets from the telephony interfaces, although in this case the PC
interface 7 is used. In this manner the telephony application 25
offers the same alternatives as an ordinary telephone. For outgoing
Internet calls, the telephony application of the NT 5 is not
involved at all. For incoming calls, the configuration of the NT 5
may decide whether alerting of the telephones and a telephony
application 25 on a PC 2 should be provided or not as in the
previously described cases.
[0102] In known art Internet connections, the Internet Phone
service offered to the users normally requires that both the caller
and the receiver are connected to Internet and furthermore that
they both have a telephony application 25 running in their
computers. Since the speech information according to the present
invention is packetized in IP packages during the transmission on
the TV distribution network 8 and Internet 14 lines, there is also
a possibility for a communication between an ordinary telephone and
the Internet Phone service. One possibility is described above,
where the Internet 14 user is connected to the TV distribution
network 8.
[0103] It is also possible for a user of a TV distribution network
8 to use an ordinary telephone to reach another Internet 14 user
over the Internet Phone service. When placing the call, the caller
informs the NT 5 about the requested IP address instead of the PSTN
16 telephone number, e.g. by selecting an address from a list. Such
a situation is sketched in FIG. 6. Note that the PC 2a of user A
may not even be turned on.
[0104] The above described multi-addressing possibilities are in a
similar way present also for the pure datacom access. One PC 2 may
be assigned to one IP address, while another PC 2 may have another
IP address, which may belong to another Internet 14 service
provider.
[0105] Today, several service providers of the same service are
often available, e.g. different telephone companies. The present
invention offers a possibility for the user to select among
different service providers. One way to provide this possibility is
to have the telephony server connected to each service provider, as
shown in FIG. 7.
[0106] Above, the service supplier selection was made at the
configuration of the NT 5 and is valid for all calls from a certain
user. A change of supplier would involve a reconfiguration of the
NT 5. However, it is also possible to make the selection for each
separate call. The user will then have to provide the information
representing the desired service provider, e.g. a code or prefix.
Such information is easily integrated, for instance in the
requested telephone number. Other possibilities for selecting
service suppliers are to include at least a part of the selection
procedure in the NT 5. The selection may then be performed
automatically and the service provider can be selected based on
e.g. the time of the day, the day in the week, etc. Besides the
access to the public telephone network there are other
possibilities of voice communication. An internal voice
communication channel between the PC 2, using a telephony
application 25 or similar software, and an ordinary telephone 1,
connected to the same NT 5. If a call is requested from an ordinary
telephone, where the receiver is the telephony application 25 of
the PC 2, the NT 5 may connect the phone and the telephony
application 25 of the PC 2. This use of the NT is illustrated in
FIG. 8, where a broken line designate the connection between the
computer 2 and the phone 1a.
[0107] A generalisation of this, connecting two analogue phones 1a,
1b connected to two telephony interfaces 6 on the same NT 5, is
also possible, as is shown in FIG. 8 as a dotted line. This opens
the possibility to use the NT 5 as a service node for a local
internal phone network, e.g. between different rooms in the same
building.
[0108] The above described internal network configuration is also
possible using datacom. Different computers 2 connected to the same
NT 5 may communicate directly without using the TV distribution
network 8. The NT 5 will in such a case serve as an intranet
server.
[0109] FIG. 9 shows another possibility of communication within the
same TV distribution network 8. A user A wants to make a request
for a call to user B within the same TV distribution network 8. The
destination of the call is the ordinary telephone number of user B.
When the request of establishing a connection with user B reaches
the telephony server 15, the telephony server 15 recognises the
telephone number as one of the users in the TV distribution network
8. The call is then forwarded direct to the right end user without
passing the public PSTN network 16. Such services may therefore
supply a regional telephone network with the same extent as the TV
distribution network 8.
[0110] Also in this context, the above ideas of intra-rietwork
communication apply to datacom. In such a case, the router 24 will
recognise the external IP address as one that is connected to the
same TV distribution network 8 and thus forward the datacom traffic
directly to the receiver without passing any regular IP based
network 14.
[0111] The TV distribution network 8 is used as a distribution
medium, without influencing the TV broadcasting. However, there are
some advantageous possibilities to use the TV programs themselves
as well the available hardware. A TV channel that is broadcasted
over the TV distribution network 8 passes normally right through
the NT 5 to be presented at the TV set 3. However, as mentioned
briefly earlier, it would be possible to tap a TV channel and send
the information e.g. to the PC 2 or other device with capabilities
for visual presentation.
[0112] In a similar way information from e.g. the PC 2 may be
presented at the TV set 3 as visual information, either in a
separate free TV channel or overlaid any other TV channel.
[0113] All of the above described possibilities are possible to
achieve by configuring the NT 5 in a proper way. It is thus
convenient if the NT 5 is equipped with a WWW server, making it
possible to manage the NT 5 configuration.
[0114] The above descriptions are examples of embodiments of the
present invention. Someone skilled in the art will easily be able
to make modifications and alternatives, which also should be
considered to fall within the claims of the present invention. As
an example, in the description above it is stated that the data
representing the voice is compressed before it Is sent over the TV
distribution network 8. It is obviously also possible to exclude
this step in cases where the transmission capability is enough for
sending non-compressed calls. Similarly, the protocol stacks
presented are only examples of possible solutions and do not belong
to the scope of the invention.
[0115] Different variations are possible, depending on the
particular transmission medium used, e.g. analogue vs. digital TV
distribution networks. It is also possible to use different shared
media, i.e. the above described TV distribution network. In the
above description a DECT solution is used. In this case a DVB is
used as TV distribution network. Since the data communication
channels are independent of the broadcasting channels, the DECT
solution may also be used in connection with analogue TV
networks.
[0116] According to the specification "Draft specification of DVB
Interaction Channel based on DECT", DVB-RC-165 rev 7, vers. 4.0,
Mar. 27, 1997 it can be applied to various TV broadcasting systems,
such as satellite. cable, SMATV (Satellite Master Antenna
Television) terrestial, DVB-MC (Microwave as cable), DVB-MS
(Microwave as Satellite) or any future DVB broadcasting system.
[0117] DVB is also developing for including MPEG (Motion Picture
Expert Group) coded video. This implies that the downstream
information streams becomes bursty, why space for multiplexing
other types of streams becomes available. In such systems, the
interactive downstream channels are provided by the broadcasting
protocols, while DECT is used only for the upstream channels.
[0118] The DECT scheme for interaction channels is one possible
example. Other solutions are also available in the state of the
art. The IEEE 802.14 standard discloses a standard for the physical
layer and a MAC protocol for CATV networks.
[0119] The NT 5 has above been described without stating anything
about the physical realisation. It is obvious for anyone skilled in
the art that the NT 5 may be integrated into one single unit as
well as be separated into two or more units.
[0120] In the description above, only the case, where one router 24
and telephony server 15, respectively are connected to one single
IP access server 12, is discussed. It is of course possible for the
telephony server 15 and router 24 to be a part of any kind of
network system, including several IP access servers 12 or not,
eventually leading to a service provider network 14, 16. Above
nothing has been described about the physical realisation of these
units. It is obvious for anyone skilled in the art that the IP
access server 12. the telephony server 15 and the router 24 may be
integrated into one single unit. forming a network node, as well as
be separated into two or more units.
[0121] The interfaces of the NT 5 may also be assigned to other
applications than PC:s 2 or telephones 1, parallel to what was
discussed in the Swedish patent applications cited above. Such
other interface possibilities are e.g. interfaces for DECT systems,
LAN's, digital telephones, or phones connected through LAN's. It is
thus obvious that also such applications have the same type of
communication possibilities, both internal and external as
described above.
* * * * *
References