Carrierless backwards compatible data neworking transmitter, receiver, and signal format
New version packet data devices support a backwards-compatible signal format. New version devices operate within a first frequency band while old version devices operate within a second frequency band. The first frequency band differs from but overlaps with the second frequency band. The new version devices may operate on a first carrier frequency (within the first frequency band) while old version devices may operate at a second carrier frequency (within the second frequency band). The new version devices and/or the old version devices may also support carrier-less modulations. 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 payload of the new version signal may be formed in the same manner or may be formed in have a wider bandwidth, higher data rate format.
1. A method for forming a backwards-compatible home networking signal by a new version device, the method comprising:
forming a baseband modulated signal;
up sampling the baseband modulated signal to create an up sampled signal having a plurality of spectral copies of the baseband modulated signal;
transmit filtering the plurality of spectral copies of the baseband modulated signal with a transmit filter corresponding to a first frequency band of the new version device, wherein the first frequency band differs from a second frequency band of an old version device; and
wherein the transmit filtered plurality of spectral copies of the baseband modulated signal includes a spectral copy of the baseband modulated signal that resides within the second frequency band.
2. The method of claim 1 , further comprising shifting in frequency the baseband modulated signal prior to up sampling the baseband modulated signal.
3. The method of claim 2 , wherein:
the baseband modulated signal includes a non-payload portion and a payload portion; and
only the non-payload portion of the baseband modulated signal is frequency shifted.
4. The method of claim 2 , wherein:
the baseband modulated signal includes a non-payload portion and a payload portion;
when communicating with another new version device, only the non-payload portion of the baseband modulated signal is frequency shifted; and
when communicating with the old version device, both the non-payload portion and the payload portion of the baseband modulated signal are frequency shifted.
5. The method of claim 2 , wherein shifting in frequency the baseband modulated signal comprises inverting every other symbol of the baseband modulated signal.
6. The method of claim 2 , wherein an amount of frequency shift applied is based upon a carrier frequency of the old version device.
7. The method of claim 2 , wherein an amount of frequency shift applied is upon:
a symbol rate of the baseband modulated signal; and
a carrier frequency of the old version device.
8. The method of claim 1 , wherein:
the first frequency band is 4–21 MHz; and
the second frequency band is 4–10 MHz.
9. The method of claim 1 , wherein:
the first frequency band is 4–28 MHz; and
the second frequency band is 4–10 MHz.
10. The method of claim 1 , wherein:
the first frequency band overlaps with the second frequency band; and
the spectral copy of the baseband modulated signal that resides within the second frequency band resides within a portion of the first frequency band that overlaps with the second frequency band.
11. A method for forming a data networking signal for use within a data network shared by new version devices operating in a first frequency band and old version devices operating in a second frequency band, the method comprising:
forming a baseband modulated signal that carries a header and a payload;
frequency shifting portions of the baseband modulated signal that carry the header;
up sampling the baseband modulated signal to create an up sampled signal having a plurality of spectral copies of the baseband modulated signal;
transmit filtering the up sampled signal with a transmit filter corresponding to a first frequency band of the new version device, wherein the first frequency band differs from a second frequency band of an old version device; and
wherein the transmit filtered up sampled signal includes a spectral copy of the baseband modulated signal within the second frequency band.
12. The method of claim 11 , wherein portions of the baseband signal that carry the payload are not frequency shifted.
13. The method of claim 11 , wherein:
when communicating with another new version device, only portions of the baseband modulated signal that carry a preamble, the header, and a trailer are frequency shifted; and
when communicating with the old version device, all portions of the baseband modulated signal are frequency shifted.
14. The method of claim 11 , wherein shifting in frequency the baseband modulated signal comprises inverting every other symbol of the baseband modulated signal.
15. The method of claim 11 , wherein an amount of frequency shift applied is based upon a carrier frequency of the old version device.
16. The method of claim 11 , wherein an amount of frequency shift applied is based upon:
a symbol rate of the baseband modulated signal; and
a carrier frequency of the old version device.
17. The method of claim 11 , wherein:
the first frequency band is 4–21 MHz; and
the second frequency band is 4–10 MHz.
18. The method of claim 11 , wherein:
the first frequency band is 4–28 MHz; and
the second frequency band is 4–10 MHz.
19. The method of claim 11 , wherein:
the first frequency band overlaps with the second frequency band; and
the spectral copy of the baseband modulated signal that resides within the second frequency band resides within a portion of the first frequency band that overlaps with the second frequency band.
20. A data network transmitter of a new version device comprising:
a data framer that receives bits of data and that frames the bits of data to produce a data frame;
a baseband modulator coupled to the data framer that baseband modulates the data frame to form a baseband modulated signal that carries the data frame;
an up sampler coupled to the baseband modulator that up samples the baseband modulated signal to create an up sampled signal having a plurality of spectral copies of the baseband modulated signal;
a transmit filter coupled to the up sampler that transmit filters the up sampled signal, wherein the transmit filter has a frequency band corresponding to a first frequency band of the new version device, and wherein the first frequency band differs from a second frequency band of an old version device; and
wherein the transmit filtered up sampled signal includes a plurality of spectral copies of the baseband modulated signal, one of which resides within the second frequency band.
21. The data network transmitter of claim 20 , further comprising a frequency shifter that frequency shifts the baseband modulated signal.
22. The data network transmitter of claim 21 , wherein the frequency shifter frequency shifts portions of the baseband modulated signal corresponding to non-payload portions of the data frame.
23. The data network transmitter of claim 21 , wherein:
the baseband modulated signal includes a non-payload portion and a payload portion;
when the data network transmitter communicates with a new version device, only the non-payload portion of the baseband modulated signal is frequency shifted; and
when the data network transmitter communicates with an old version device, both the non-payload portion and the payload portion of the baseband modulated signal are frequency shifted.
24. The data network transmitter of claim 21 , wherein the frequency shifter shifts the frequency of the baseband modulated signal by inverting symbols of the baseband modulated signal.
25. The data network transmitter of claim 21 , wherein the frequency shifter shifts the frequency of the baseband modulated signal by inverting every other symbol of the baseband modulated signal.
26. The data network transmitter of claim 21 , wherein an amount of frequency shift applied is based upon a carrier frequency of the old version device.
27. The data network transmitter of claim 21 , wherein an amount of frequency shift applied is based upon:
a symbol rate of the baseband modulated signal; and
a carrier frequency of the old version device.
28. The data network transmitter of claim 20 , wherein:
the first frequency band is 4–21 MHz; and
the second frequency band is 4–10 MHz.
29. The data network transmitter of claim 20 , wherein:
the first frequency band is 4–28 MHz; and
the second frequency band is 4–10 MHz.
30. The data network transmitter of claim 20 , wherein the transmit filter has a frequency band of 4–21 MHz.
31. The data network transmitter of claim 20 , wherein the transmit filter has a frequency band of 4–28 MHz.
32. A method for forming a backwards-compatible home networking signal by a new version device, the method comprising:
forming a baseband modulated signal;
up sampling the baseband modulated signal to create a plurality of spectral copies of the baseband modulated signal;
transmit filtering the plurality of spectral copies of the baseband modulated signal with a transmit filter corresponding to a first frequency band of the new version device, wherein the first frequency band differs from a second frequency band of an old version device; and
wherein the transmit filtered plurality of spectral copies of the baseband modulated signal includes a spectral copy of the baseband modulated signal that resides within the second frequency band.
33. The method of claim 32 , wherein:
the baseband modulated signal includes a non-payload portion and a payload portion; and
only the non-payload portion of the baseband modulated signal is up sampled to form the plurality of spectral copies of the baseband modulated signal.
34. The method of claim 33 , wherein the non-payload portion comprises:
a preamble and a header that precede the payload portion; and
a trailer follows the payload portion.
35. The method of claim 32 , wherein:
the baseband modulated signal includes a non-payload portion and a payload portion;
when communicating with another new version device, only the non-payload portion is up sampled to create the plurality of spectral copies of the baseband modulated signal; and
when communicating with the old version device, both the non-payload portion and the payload portion are spectrally copied.
36. The method of claim 32 , wherein:
the first frequency band overlaps with the second frequency band; and
the spectral copy of the baseband modulated signal that resides within the second frequency band resides within a portion of the first frequency band that overlaps with the second frequency band.
37. The method of claim 36 , wherein the transmit filter has a frequency band corresponding to the first frequency band of the new version device.
38. The method of claim 32 , wherein the transmit filter has a frequency band of 4–21MHz.
39. The method of claim 32 , wherein the transmit filter has a frequency band of 4–28MHz.
40. A method for forming a data networking signal for use within a data network shared by first device types operating in a first frequency band and second device types operating in a second frequency band, the method comprising:
forming a baseband modulated signal that carries a data frame having a header and a payload;
up sampling the baseband modulated signal to create a plurality of spectral copies of the baseband modulated signal;
transmit filtering the plurality of spectral copies of the baseband modulated signal with a transmit filter corresponding to the first frequency band, wherein the first frequency band differs from the second frequency band; and
wherein the transmit filtered plurality of spectral copies of the baseband modulated signal includes a spectral copy of the baseband modulated signal that resides within the second frequency band.
41. The method of claim 40 , wherein:
the first frequency band overlaps with the second frequency band; and
the spectral copy of the baseband modulated signal that resides within the second frequency band resides within a portion of the first frequency band that overlaps with the second frequency band.
42. The method of claim 40 , wherein a transmit filter used for transmit filtering has a frequency band that extends across both the first frequency band and the second frequency band.