Gateway with voice

• US 6,765,931 B1
• Filed: 04/13/2000
• Issued: 07/20/2004
• Est. Priority Date: 04/13/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hartman, David, Rabenko, Theodore F., Thi, James C. H.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): SCHULTZ, WILLIAM C
• Application Number:
  US09/548,400
• Time in Patent Office: 1,559 Days
• Field of Search: 370/271, 370/285, 370/286, 370/287, 370/289, 370/352, 370/353, 370/356, 370/493, 370/495
• US Class Current: 370/493
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers
• CPC Class Codes: H04B 3/234 using double talk detection
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/5692 Selection among different networks
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 65/1026 at the edge
• CPC Class Codes: H04L 65/1036 at the edge
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42
• CPC Class Codes: H04M 7/125 Details of gateway equipment
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 7/10 Adaptations for transmission by electrical cable H04N7/12 takes precedence

Abstract

In one aspect of the present invention, a network gateway is configured to facilitate on line and off line bi-directional communication between a number of near end data and telephony devices with far end data termination devices via a hybrid fiber coaxial network and a cable modem termination system. The described network gateway combines a QAM receiver, a transmitter, a DOCSIS MAC, a CPU, a voice and audio processor, an Ethernet MAC, and a USB controller to provide high performance and robust operation.

Claims

1. A cable modem, comprising:

a network port to interface with a cable head end;

a telephony port to interface with a telephony device;

a data port to interface with a data terminal;

a processor coupled to each of the ports; and

an echo canceller adapted to cancel a cable head end echo on voice signal flowing from the telephony device to the cable head end.

2. The cable modem of claim 1 further comprising a transceiver coupled between the processor and the network port.

3. The cable modem of claim 2 wherein the transceiver comprises a media access controller (MAC) coupled to the processor, and a modulator and a demodulator both disposed between the MAC and the network port.

4. The cable modem of claim 1 wherein the processor determines whether voices signals from the network port are destined for the data port or the telephony port and couples the voice signals to one of the data port and telephony port based on such determination.

5. The cable modem of claim 1 further comprising a voice circuit coupled between the telephony port and the processor.

6. A gateway, comprising:

a network port to interface with a cable head end;

a telephony port to interface to a telephony device;

a data port to interface to a data terminal;

a processor coupled to each of the ports;

a transceiver disposed between the processor and the network port, the transceiver being capable of transmitting and receiving packets of voice signals, packets of data signals, and a television signal; and

an echo canceller adapted to cancel a cable head end echo on a voice signal flowing from the telephony device to the cable head end.

7. The gateway of claim 6 wherein the transceiver comprises a media access controller (MAC) coupled to the processor, and a modulator and a demodulator both disposed between the MAC and the network port.

8. The gateway of claim 6 wherein the processor determines whether the voices signals from the network port are destined for the data port or the telephony port and couples the voice signals to one of the data port and telephony port based on such determination.

9. The gateway of claim 6 further comprising a voice circuit coupled between the telephony port and the processor.

10. A method of processing signals, comprising:

exchanging voice signals between a cable head end and a telephony device, wherein the voice exchange comprises canceling a cable head end echo on a telephony signal flowing from the telephony device to the cable head end;

exchanging data signals between the cable head end and a data terminal; and

receiving a television signal from the cable head end.

11. The method of claim 10 further comprising demodulating the signals flowing from the head end to the telephony device and the data terminal, and modulating the signals flowing from the telephony device and the data terminal to the cable head end.

12. The method of claim 10 wherein the data signal exchange comprises receiving and transmitting the data signals to the data terminal over a local area network (LAN).

13. The method of claim 10 wherein the voice signal exchange comprises receiving and transmitting the voice signals to the telephony device over a telephone line.

14. The method of claim 13 wherein the voice signal exchange further comprises exchanging second voice signals between the cable head end and a second telephony, the second voice signal exchange comprising receiving and transmitting the second voice signals to the second telephony device over the LAN.

15. The method of claim 10 wherein the echo cancellation comprises adaptively filtering a cable head end signal from the cable head end based on adaptation coefficients, detecting whether voice is present on the telephony signal, holding the adaptation coefficients constant when voice is present, and canceling the cable head end echo from the telephony signal after the adaptation coefficients are held constant.

16. The method of claim 15 wherein the echo cancellation further comprises subtracting the adaptively filtered cable head end signal from the telephony signal.

17. The method of claim 15 wherein the echo cancellation further comprises delaying the cancellation of the echo from the telephony signal for a time after the detection of voice.

18. The method of claim 15 wherein the detection of voice comprises estimating an absolute value of the cable head end signal, estimating a maximum of the telephony signal, comparing the absolute value of the cable head end signal to the estimated maximum of the telephony signal, and detecting voice on the telephony signal as a function of the comparison.

19. The method of claim 15 wherein the pre-conditioning the telephony signal comprises adaptively filtering the cable head end signal and subtracting the adaptively filtered cable head end signal from the telephony signal.

20. The method of claim 10 wherein the voice exchange synchronizing the voice signal between the cable head end and the telephony device.

21. The method of claim 20 wherein the voice synchronization comprises generating an error signal as a function of a difference between a cable head end clock and a voice exchange clock, and fractionally resampling the voice signals as a function of the error signal.

22. The method of claim 21 wherein the generation of the error signal comprises driving a first counter with the cable head end clock, driving a second counter with the voice exchange clock, wherein the error signal is generated by dividing an output of the first counter by an output of the second counter.

23. The method of claim 22 wherein the voice synchronization further comprises fractionally up-sampling the voice signals by the error signal when the output of the first counter exceeds the output of the second counter.

24. The method of claim 22 wherein the voice synchronization further comprises fractionally down-sampling the voice signals by the error signal when the output of the first counter is less than the output of the second counter.

25. The method of claim 22 wherein the voice synchronization further comprises filtering the output of said first and second clocks, wherein the error signal is generated by dividing the filtered output of the first counter by the filtered output of the second counter.