System and method for transmitting ancillary data
A method and system for encoding ancillary information at a transmitter in a high-speed communications network, the method comprising: generating an electromagnetic interference (EMI) reduction signal; receiving an ancillary data symbol; generating an EMI reduction signal variation based on the ancillary data symbol; and varying a characteristic of the EMI reduction signal based on the generated EMI reduction signal variation to encode the ancillary data symbol in the varied EMI reduction signal.
1. A method for decoding ancillary information at a receiver in a high-speed communications network, the method comprising:
receiving an EMI-reduced message signal transmitted with a spread-spectrum clocking (SSC) profile, the SSC profile having an SSC profile variation encoding an ancillary data symbol;
extracting the SSC profile variation at a demodulator;
receiving a pilot symbol;
correcting the extracted SSC profile variation according to the pilot symbol; and
decoding the ancillary data symbol from the extracted SSC profile variation at a decoder, including comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol, wherein decoding comprises comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol.
2. The method of claim 1 , wherein decoding comprises comparing the SSC profile variation to a mask corresponding to the ancillary data symbol.
3. The method of claim 1 , further comprising:
correcting the extracted SSC profile variation by the difference between the magnitude of the maximum peak and the magnitude of the minimum peak of the extracted SSC profile variation, the expected magnitude of the maximum peak equal to the expected magnitude of the minimum peak.
4. The method of claim 1 , further comprising:
correcting the extracted SSC profile variation by the average magnitude of the extracted SSC profile variation, the expected average magnitude equal to zero.
5. The method of claim 1 , wherein the SSC profile has a constant cycle duration, and the SSC profile comprises a plurality of sections, the sum of the durations of all the SSC profile sections being equal to the constant cycle duration of the SSC profile.
6. A method for decoding ancillary information at a receiver in a high-speed communications network, the method comprising:
receiving an EMI-reduced message signal transmitted with a spread-spectrum clocking (SSC) profile, the SSC profile having an SSC profile variation encoding an ancillary data symbol;
extracting the SSC profile variation at a demodulator;
decoding the ancillary data symbol from the extracted SSC profile variation at a decoder, including comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol, wherein decoding comprises comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol;
selecting an EMI reduction signal variation bin corresponding to the extracted EMI reduction signal variation, the EMI reduction signal bin being a nominal value mapped to a range of EMI reduction signal variation values; and
decoding, at a decoder, the ancillary data symbol from the selected EMI reduction signal variation bin.
7. The method of claim 6 , wherein the range of EMI reductions signal variation values is at least twice the expected maximum constant difference between a received symbol rate and a transmitted symbol rate.
8. A receiver for decoding ancillary information in a high-speed communications network, the receiver comprising:
an input configured to receive an EMI-reduced message signal transmitted with a spread-spectrum clocking (SSC) profile, the SSC profile having an SSC profile variation encoding an ancillary data symbol;
a demodulator configured to extract the SSC profile variation, receive a pilot symbol, and correct the extracted SSC profile variation according to the pilot symbol; and
a decoder for decoding the ancillary data symbol from the SSC profile variation, including comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol, wherein decoding comprises comparing a peak-to-peak amplitude of the SSC profile variation to an expected peak-to-peak amplitude corresponding to the ancillary data symbol.