Methods and systems for multimedia communication via public telephone networks

• US 6,081,291 A
• Filed: 04/16/1997
• Issued: 06/27/2000
• Est. Priority Date: 12/30/1994
• Status: Expired due to Term

• Current Assignee: Pragmatus AV LLC (Pragmatus, LLC)
• Original Assignee: VCT Incorporated
• Inventors: Ludwig, Lester Frank Jr.
• Primary Examiner(s): Loomis, Paul
• Assistant Examiner(s): Eng, George
• Application Number:
  US08/842,745
• Time in Patent Office: 1,168 Days
• Field of Search: 348/12-20, 370/84, 370/260, 370/396-398, 364/514, 395/162, 395/200.04, 379/93.01, 379/93.07, 379/93.09, 379/93.14, 379/201, 379/202, 379/220
• US Class Current: 348/14.11
• CPC Class Codes: H04L 12/2859 Point-to-point connection between the data network and the subscribers encapsulation H04L12/4633; virtual LANs H04L12/4641; routing of packets H04L45/00
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/4038 with floor control
• CPC Class Codes: H04L 65/612 for unicast
• CPC Class Codes: H04L 65/762 at the source reformatting of additional data in video distribution servers H04N21/2355
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 3/5307 for recording messages comprising any combination of audio and non-audio components
• CPC Class Codes: H04M 3/567 Multimedia conference systems
• CPC Class Codes: H04M 7/00 Arrangements for interconnection between switching centres
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 21/6137 involving transmission via a telephone network, e.g. POTS
• CPC Class Codes: H04N 21/6187 involving transmission via a telephone network, e.g. POTS
• CPC Class Codes: H04N 7/10 Adaptations for transmission by electrical cable H04N7/12 takes precedence
• CPC Class Codes: H04N 7/108 the cable being constituted by a pair of wires
• CPC Class Codes: H04N 7/147 Communication arrangements, e.g. identifying the communication as a video-communication, intermediate storage of the signals selecting H04Q
• CPC Class Codes: H04N 7/15 Conference systems

Abstract

Methods and systems are disclosed for providing multimedia telecommunication services to multimedia workstations. The multimedia workstations communicate with a multimedia central office which includes a digital switch complex coupled to a public digital telephone network, and at least one twisted pair transceiver coupled to at least one twisted pair link in a telephone loop plant. The multimedia central office further includes at least one switch complex operatively associated with the digital switch complex and the at least one twisted pair transceiver. The multimedia central office is capable of transceiving signals with multimedia workstations interfaced to the public digital telephone network, and with multimedia workstations interfaced to the at least one twisted pair link in the telephone loop plant. The signals which are transceived include audio signals, video signals, and digital data signals used in providing the multimedia telecommunication services.

Claims

1. A system for providing a plurality of multimedia telecommunication services to a plurality of multimedia workstations at least two of which are distributed among a first premise and a second premise, the system comprising:

a multimedia central office located at a third premise, the multimedia central office including;

a digital switch complex coupled to at least one of the plurality of workstations via a public digital telephone network;

at least one twisted pair transceiver coupled to a second one of the plurality of workstations via at least one twisted pair link in a telephone loop plant; and

at least one switch complex operatively associated with the digital switch complex and the at least one twisted pair transceiver;

wherein the multimedia central office transceives signals with one of the multimedia workstations interfaced to the public digital telephone network, transceives signals with one of the multimedia workstations interfaced to the twisted pair link in the telephone loop plant, and the signals include audio signals, video signals, and digital data signals.

2. The system of claim 1 wherein the multimedia telecommunication services include application sharing between at least two of the multimedia workstations.

3. The system of claim 1 wherein the multimedia telecommunication services include window sharing between at least two of the multimedia workstations.

4. The system of claim 1 wherein the multimedia telcommunication services include multimedia messaging between at least two of the multimedia workstations.

5. The system of claim 1 wherein the digital switch complex is coupled to a third-party network, wherein the multimedia telecommunication services provided by the system include providing a gateway to the third-party network.

6. The system of claim 1 wherein the multimedia central office is networked to a second multimedia central office via at least one common carrier digital transmission link coupled to the digital switch complex.

7. The system of claim 6 wherein each of at least two of the multimedia workstations is coupled to the multimedia central office by a corresponding one of at least two dedicated digital carriers, and wherein the multimedia central office concentrates data received on the at least two dedicated digital carriers for transmission to the second multimedia central office.

8. The system of claim 1 further comprising an internal premise communication system which couples at least two of the multimedia workstations to the multimedia central office, wherein the at least two of the multimedia workstations share access to the multimedia central office via the internal premise communication system.

9. The system of claim 1 wherein at least two of the multimedia workstations are located within a common user premise.

10. The system of claim 1 wherein the multimedia workstations are located at a plurality of user premises.

11. The system of claim 1 wherein the multimedia central office transceives audio signals having an effective bandwidth of at least 5 kHz, color video signals having an effective bandwidth of at least 3 MHz, and digital data signals having a bit rate of at least 128 kbps via the at least one twisted pair link.

12. The system of claim 1 wherein an analog video signal is communicated between the multimedia central office and at least one of the multimedia workstations using a plurality of space division video signals, each of the space division video signals being transmitted over a corresponding one of a plurality of twisted pair links.

13. The system of claim 12 wherein the twisted pair transceiver comprises:

a plurality of filters responsive to the analog video signal, each of the filters passing a corresponding band of frequencies contained within the analog video signal and producing a corresponding filtered signal based thereup-on;

at least one frequency shifter for producing a corresponding frequency-shifted signal based upon the filtered signal from a corresponding one of the filters; and

a plurality of transmitter each transmitting the corresponding frequency-shifted signal over a corresponding one of the plurality of twisted pair links.

14. The system of claim 12 wherein the at least one twisted pair transceiver includes:

a plurality of receivers which receives the space division video signals;

at least one frequency shifter responsive to the receivers, each of the at least one frequency shifter producing a corresponding reconstructed signal; and

a mixer responsive to each corresponding reconstructed signal to form a reconstructed analog video signal.

15. The system of claim 12 wherein the analog video signal contains a chrominance signal and a luminance signal, the chrominance signal being transmitted over a first one of the twisted pair links and the luminance signal being transmitted over a second one of the twisted pair links.

16. The system of claim 12 wherein the at least one twisted pair transceiver includes:

a band-pass filter which produces a band-pass signal in dependence upon the analog video signal, the analog video signal containing a chroma carrier signal and sidebands associated therewith, the band-pass filter passing the chroma carrier signal and the sidebands associated therewith;

a frequency down-shifter, in communication with the band-pass filter, which produces a frequency shifted signal based upon the band-pass signal;

a low-pass filter which produces a low-pass signal in dependence upon the analog video signal, the low-pass filter having a cut-off frequency less than the frequency of the chroma carrier signal;

a first transmitter which transmits a first signal over a first of the twisted pair links, the first signal based upon the frequency shifted signal; and

a second transmitter which transmits a second signal over a second of the twisted pair links, the second signal based upon the low-pass signal.

17. The system of claim 12 further comprising a mixer which mixes an audio signal with one of the space-division video signals to form a mixed signal, wherein the mixed signal is transmitted over one of the twisted pair links corresponding to the space division video signals.

18. The system of claim 17 further comprising a modulator which modulates the audio signal for application to the mixer.

19. The system of claim 1 wherein a digital signal is communicated between the multimedia central office and one of the multimedia workstations over a plurality of twisted pair links using digital inverse multiplexing, wherein a corresponding bit stream carried over each of the twisted pair links has a bit rate higher than that for an ISDN basic rate interface.

20. The system of claim 19 further comprising:

a first digital inverse multiplexer which produces a plurality of digital streams each having a bit rate lower than that of the digital signal; and

a second digital inverse multiplexer in communication with the first digital inverse multiplexer via the plurality of twisted pair links, the second digital inverse multiplexer producing a reconstructed digital signal from the plurality of digital streams.

21. The system of claim 20 further comprising:

a first codec which forms the digital signal in dependence upon an analog signal; and

a second codec coupled to the second digital inverse multiplexer, which forms a reconstructed analog signal from the reconstructed digital signal.

22. A method of providing a plurality of multimedia telecommunication services to a plurality of multimedia workstations at least two of which are distributed among first and second premises, the method comprising:

providing a multimedia central office located at a third premise capable of providing the multimedia telecommunication services;

coupling at least one of the multimedia workstations to the multimedia central office by the public digital telephone network;

coupling at least one of the multimedia workstations to the multimedia central office by at least one twisted pair link within a telephone loop plant;

transceiving signals between the multimedia central office and the multimedia workstations via the public digital telephone network; and

transceiving signals between the multimedia central office and the multimedia workstations via the telephone loop plant;

wherein the signals include audio signals, video signals, and digital data signals.

23. The method of claim 22 wherein the multimedia telecommunication services include application sharing between at least two of the multimedia workstations.

24. The method of claim 22 wherein the multimedia telecommunication services include window sharing between at least two of the multimedia workstations.

25. The method of claim 22 wherein the multimedia telcommunication services include multimedia messaging between at least two of the multimedia workstations.

26. The method of claim 22 further comprising the steps of:

coupling the multimedia central office to a third-party network; and

providing, to at least one of the multimedia workstations, a gateway to the third-party network.

27. The method of claim 22 further comprising the steps of:

providing a second multimedia central office; and

networking the multimedia central office to the second multimedia central office via at least one common carrier digital transmission link.

28. The method of claim 27 wherein each of at least two of the multimedia workstations is coupled to the multimedia central office by a corresponding one of at least two dedicated digital carriers, the method further comprising the step of concentrating data received on the at least two dedicated digital carriers for transmission to the second multimedia central office.

29. The method of claim 22 further comprising the step of:

coupling at least two of the multimedia workstations to the multimedia central office by an internal premise communication system, wherein the at least two of the multimedia workstations share access to the multimedia central office via the internal premise communication system.

30. The method of claim 22 wherein the first at least one and the second at least one of the multimedia workstations are located within a common user premise.

31. The method of claim 22 wherein the multimedia workstations are located at a plurality of user premises.

32. The method of claim 22 wherein the multimedia central office transceives audio signals having an effective bandwidth of at least 5 kHz, color video signals having an effective bandwidth of at least 3 MHz, and digital data signals having a bit rate of at least 128 kbps via the at least one twisted pair.

33. The method of claim 22 wherein the step of transceiving includes a step of communicating an analog video signal between the multimedia central office and one of the second at least one of the multimedia workstations using a plurality of space division video signals, each of the space division video signals transmitted over a corresponding one of a plurality of twisted pair links.

34. The method of claim 33 wherein the step of communicating includes the steps of:

producing a plurality of filtered signals based upon the analog video signal, each of the filtered signals passing a corresponding band of frequencies contained within the analog video signal;

frequency shifting each of at least one of the filtered signals to produce at least one frequency shifted signal; and

transmitting each of the at least one frequency-shifted signal over a corresponding one of the plurality of twisted pair links.

35. The method of claim 33 wherein the step of communicating includes the steps of:

receiving each of at least one space division video signal;

frequency shifting the at least one space division video signal to produce at least one reconstructed signal; and

mixing the at least one reconstructed signal to form a reconstructed analog video signal.

36. The method of claim 33 wherein the analog video signal contains a chrominance signal and a luminance signal, and wherein the step of communicating includes the steps of:

transmitting the chrominance signal over a first of the twisted pair links; and

transmitting the luminance signal over a second of the twisted pair links.

37. The method of claim 33 wherein the analog video signal contains a chroma carrier signal and sidebands associated therewith, and wherein the step of communicating includes the steps of:

band-pass filtering the analog video signal to produce a band-pass signal containing the chroma carrier signal and the sidebands associated therewith;

frequency down-shifting the band-pass signal to produce a frequency shifted signal;

low-pass filtering the analog video signal to produce a low-pass signal containing frequencies less than the frequency of the chroma carrier signal;

transmitting a first signal over a first of the twisted pair links based upon the frequency shifted signal; and

transmitting a second signal over a second of the twisted pair links based upon the low-pass signal.

38. The method of claim 33 wherein the analog video signal contains a chroma carrier signal and sidebands associated therewith, and wherein the step of communicating includes the steps of:

receiving a first signal via a first of the twisted pair links;

receiving a second signal via a second of the twisted pair links;

frequency up-shifting the first signal to produce a third signal; and

mixing the third signal and the second signal to form a reconstructed video signal.

39. The method of claim 33 further comprising a step of mixing an audio signal with one of the space division video signals to form a mixed signal, wherein the mixed signal is transmitted over the one of the twisted pair links corresponding to the one of the space division video signals.

40. The method of claim 22 wherein the step of transceiving the second plurality of signals includes the step of communicating a digital signal over a plurality of twisted pair links using digital inverse multiplexing, wherein a corresponding bit stream carried over each of the twisted pair links has a bit rate higher than that for an ISDN basic rate interface.

41. The method of claim 40 wherein the step of communicating includes the steps of:

inverse multiplexing the digital signal to produce a plurality of digital streams each having a bit rate lower than that of the digital signal;

transmitting each of the digital streams via a corresponding one of the twisted pair links;

receiving the digital streams; and

inverse multiplexing the digital streams to produce a reconstructed digital signal.

42. The method of claim 41 further comprising the steps of:

forming the digital signal in dependence upon an analog signal; and

forming a reconstructed analog signal from the reconstructed digital signal.