Home phone line networking next generation enhancements

• US 7,327,765 B1
• Filed: 04/22/2003
• Issued: 02/05/2008
• Est. Priority Date: 02/15/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Ojard, Eric J.
• Primary Examiner(s): Patel; Jay K.
• Assistant Examiner(s): Wong; Blanche
• Application Number:
  US10/421,981
• Time in Patent Office: 1,750 Days
• Field of Search: 375/295, 370/482
• US Class Current: 370/482
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating

Abstract

New version devices of a home phone line network may operate on a first carrier frequency (within the new version frequency band) while old version devices may operate at a second carrier frequency (within the old version frequency band). Preamble, header, and trailer portions of a new version signal include a plurality of spectral copies of a baseband modulated signal. One or more of these spectral copies of the baseband modulated signal is/are indistinguishable from corresponding components of an old version signal. The new version signal is transmit filtered to have a negatively sloping power spectral density in order to maintain a constant power level in relation to old version signals and to have slope that is opposite of binder crosstalk so as to form, with the average crosstalk, a constant level white noise floor.

Claims

1. A backwards-compatible home phone line network transmitter for communicating over a home network that supports both new version devices and old version devices, the backwards-compatible home phone line network transmitter comprising:

digital processing circuitry for producing data bits corresponding to home networking frames for transmission over the home network;

a baseband encoder that constellation encodes the data bits corresponding to the home networking frames to form a digitally modulated signal;

a transmit filter coupled to receive the digitally modulated signal, the transmit filter transmit filtering the digitally modulated signal to produce a transmit signal, wherein the transmit signal has a sloping power spectral density (PSD) that meets signal format requirements of both an old version signal and a new version signal, wherein the sloping PSD of the transmit signal produced by the transmit filter slopes downward as frequency increases in a new version frequency band, wherein the new version frequency band is wider than and overlays an old version frequency band.

2. The backwards-compatible home phone line network transmitter of claim 1 further comprising an up-sampling low pass filter operably coupled between the baseband encoder and the transmit filter that receives the digitally modulated signal and that produces a plurality of spectral copies of the digitally modulated signal.

3. The backwards-compatible home phone line network transmitter of claim 1 further including an up-sampling block coupled between the baseband encoder and the transmit filter that up converts in frequency the digitally modulated signal from baseband to a transmit band that corresponds to the new version frequency band.

4. The backwards-compatible home phone line network transmitter of claim 1 wherein the downward slope of the sloping PSD of the transmit signal produced by the transmit filter corresponds to an inverse of an average crosstalk gain for a servicing home phone line networking media.

5. The backwards-compatible home phone line network transmitter of claim 1 wherein a maximum PSD of the new version signal produced by the transmitter is less than a maximum PSD for old version signal but has a magnitude sufficient to be sensed by the old version devices of the home network.

6. The backwards-compatible home phone line network transmitter of claim 1 wherein a minimum PSD of the transmit signal produced by the transmit filter corresponds to a maximum frequency of the transmit signal produced by the transmit filter.

7. The backwards-compatible home phone line network transmitter of claim 1 wherein the sloping PSD of the transmit signal produced by the transmit filter has a slope approximately equal to −

15 dB per 10 MHz, and wherein the sloping PSD of the transmit signal produced by the transmit filter extends to a minimum PSD value.

8. The backwards-compatible home phone line networking transmitter of claim 1 wherein a total transmit power of the new version signal produced by the transmitter in the frequency band of the new version signal is equal to a total transmit power of an old version signal transmitted by an old version device in the old version frequency band.

9. The backwards-compatible home phone line networking transmitter of claim 1 wherein the old version signal frequency band spans from 4 MHz to 10 MHz and wherein the new version signal frequency band spans from 4 MHz to one of 21 MHz or 28 MHz.

10. The backwards-compatible home phone line networking transmitter of claim 1 wherein the transmitter generates a preamble and header at a 2 Mbaud data rate carrying two bits per symbol and a payload with variable symbol and bit rates.

11. The backwards-compatible home phone line networking transmitter of claim 10 wherein the payload with variable symbol and bit rates are transmitted in one of a plurality of frequency bands of the new version signal corresponding to a receiving device capability.

12. A method for forming a backwards-compatible home networking signal by a new version device in a home network, the method comprising:

forming a new version signal spanning a new version frequency band that overlaps an old version frequency band; and

filtering the new version signal to produce a sloping power spectral density (PSD) that meets signal format requirements for an old version signal, the new version signal having a sloping PSD that slopes downward as frequency increases.

13. The method of claim 12, wherein the slope of the sloping PSD for the new version signal corresponds to an inverse of an average crosstalk gain for a servicing home phone line network media.

14. The method of claim 12 wherein the new version signal has a maximum PSD value that is slightly below a maximum PSD of the old version signal and can readily be detected by an old version device.

15. The method of claim 12 wherein the new version signal has a maximum PSD value that is sufficiently large to be detected by an old version device and the slope of the sloping PSD for the new version signal is approximately equal to −

15 dB per 10 MHz and extends to a minimum PSD value.

16. The method of claim 12 wherein a total amount of power for the new version signal is equal to a total amount of power for the old version signal transmitted over the old and new frequency bands.

17. The method of claim 12, wherein the slope of the PSD for the new version signal is approximately equal to an inverse of an average crosstalk coupling gain in a bundle of servicing home phone line network media, wherein the new version signal and an average crosstalk form a constant white noise floor in the bundle.

18. In a wire home phone line communication network that supports a plurality of legacy devices that communicate with signals having a first bandwidth and a first power spectral density (PSD), a method for forming a new version signal for a next generation home phone line network device, comprising:

generating a new version signal having a new version signal bandwidth that is wider than an old version signal bandwidth and wherein the new version signal bandwidth overlaps the old version signal bandwidth;

wherein the new version signal is formed with a transmit filter mask and has a sloping PSD with a downward slope as frequency increases in the new version bandwidth wherein the slope is equal to in magnitude and opposite in slope to the gain of crosstalk from at least one neighboring signal of at least one neighboring signal line coupled within a common binder of a plurality of signal lines; and

transmit filtering the sloping PSD of the new version signal to have a specified PSD characteristic wherein a total transmit power does not violate an old version signal PSD requirement.

19. The method of claim 18 wherein the new version signal comprises a header portion and a payload portion, wherein the data rate for the header portion is fixed and wherein the data rate for the payload portion is variable.

20. A method for transmitting a new version signal in a wired home phone line network that includes a plurality of legacy devices that transmit old version signals, as well as a plurality of next generation devices that transmit new version signals, the method comprising:

generating an old version signal format having a header portion and a payload portion, wherein the header portion including a ID of one of the plurality of legacy devices for which the payload is intended, the header portion being transmitted at a fixed data rate;

and the payload portion having a first variable data rate;

generating a new version signal format having a header portion and a payload portion, wherein the header portion including ID of one of the plurality of next generation devices for which the payload is intended, the header portion being transmitted at the fixed data rate and the payload portion being transmitted at a second variable data rate; and

transmit filtering the new version signal to produce a power spectral density (PSD) that enables one of the plurality of legacy devices to detect and read the header portion of the new version signal to determine that the corresponding payload is for another device.

21. The method of claim 20 further including transmit filtering the new generation signal to have a PSD that slopes downward with increases in frequency.

22. The method of claim 21 wherein the slope of the PSD of the new version signal counteracts gain from crosstalk coupling.

23. The method of claim 21 wherein the slope of the PSD of the new version signal is approximately equal to −

15 dB/10 MHz.

24. The method of claim 20 wherein a transmission power level of the new version signal is equal to a transmission power level of the old version signal.