Timing pilot generation for highly-spectrally-efficient communications
Methods and systems are provided for timing synchronization for reception of highly-spectrally efficient communications. An example method may include, mapping, in a transmitter, a plurality of transmit bits to a plurality of symbols at a symbol rate that is based on an oscillator signal. The plurality of symbols may be processed via a filter. The processing may result in an inter-symbol correlated (ISC) signal. The oscillator signal may be frequency divided to generate one or more pilot signals having a frequency that is a sub-harmonic of a frequency of the oscillator signal. The pilot signal may be injected into the ISC signal. The injecting may result in an ISC signal with timing carrier. The ISC signal with timing carrier may be transmitted. Gain of the one or more pilot signals may be adjusted based on a spectral mask value associated with the transmitting.
1. A system, comprising:
one or more circuits comprising:
a pulse-shaping filter that is clocked by an oscillator signal and is operable to generate an inter-symbol correlated (ISC) signal from a plurality of symbols;
a frequency-dividing circuit that is operable to:
divide said oscillator signal to generate a timing carrier; and
gain control said timing carrier;
a combiner circuit that is operable to combine said ISC signal and said timing carrier to generate a ISC-with-timing-carrier signal; and
a front-end circuit that is operable to transmit said ISC-with-timing-carrier signal onto a communication medium.
2. The system of claim 1 , wherein said symbols are N-QAM symbols and N is an integer.
3. The system of claim 1 , wherein said gain control is based on a spectral mask that is applicable to transmissions by said one or more circuits.
4. The system of claim 1 , wherein:
a frequency of said timing carrier is 1/n * Fbaud;
n is an integer greater than 2; and
Fbaud is a symbol rate of said ISC signal.
5. The system of claim 3 , wherein said gain control is based on a performance indicator communicated to the one or more circuits from a device that received said ISC-with-timing-carrier signal via said communication medium.
6. The system of claim 4 , wherein n is based on a spectral mask that is applicable to transmissions by said one or more circuits.
7. The system of claim 4 , wherein n is based on a performance indicator communicated by the one or more circuits by a receiver of said transmitted ISC-with-timing-carrier signal.
8. The system of claim 5 , wherein said performance indicator comprises one or more of:
a Signal-to-Noise Ratio (SNR);
a Symbol Error Rate (SER);
a Bit Error Rate (BER);
a measurement indicative of timing error variance; and
a measurement indicative of frequency and/or phase accuracy of said timing carrier.
9. The system of claim 7 , wherein said performance indicator comprises one or more of:
a Signal-to-Noise Ratio (SNR);
a Symbol Error Rate (SER);
a Bit Error Rate (BER);
a measurement indicative of timing error variance; and
a measurement indicative of frequency and/or phase accuracy of said timing carrier.
10. The system of claim 9 , wherein said pulse-shaping filter is a partial response filter and said ISC signal is a partial response signal.
11. A method, comprising:
performing in an electronic transmitter:
generating, via a pulse-shaping filter of said transmitter that is clocked by an oscillator signal, an inter-symbol correlated (ISC) signal from a plurality of symbols;
dividing, via a frequency-dividing circuit of said transmitter, said oscillator signal to generate a timing carrier;
gain controlling, via said frequency-dividing circuit, said timing carrier;
combining said ISC signal and said timing carrier to generate a ISC-with-timing-carrier signal; and
transmitting said ISC-with-timing-carrier signal.
12. The method of claim 11 , wherein said symbols are N-QAM symbols and N is an integer.
13. The method of claim 11 , wherein said gain controlling is based on a spectral mask that is applicable to transmissions by electronic transmitter.
14. The method of claim 11 , wherein:
a frequency of said timing carrier is 1/n * Fbaud;
n is an integer greater than 2; and
Fbaud is a symbol rate of said ISC signal.
15. The method of claim 13 , wherein said gain controlling is based on a performance indicator communicated by electronic transmitter by a receiver of said transmitted ISC-with-timing-carrier signal.
16. The method of claim 14 , wherein n is based on a spectral mask that is applicable to transmissions by said electronic transmitter.
17. The method of claim 14 , wherein n is based on a performance indicator communicated by the electronic transmitter by a receiver of said transmitted ISC-with-timing-carrier signal.
18. The method of claim 15 , wherein said performance indicator comprises one or more of:
a Signal-to-Noise Ratio (SNR);
a Symbol Error Rate (SER);
a Bit Error Rate (BER);
a measurement indicative of timing error variance; and
a measurement indicative of frequency and/or phase accuracy of said timing carrier.
19. The transmitter of claim 17 , wherein said performance indicator comprises one or more of:
a Signal-to-Noise Ratio (SNR);
a Symbol Error Rate (SER);
a Bit Error Rate (BER);
a measurement indicative of timing error variance; and
a measurement indicative of frequency and/or phase accuracy of said timing carrier.
20. The transmitter of claim 19 , wherein said pulse-shaping filter is a partial response filter and said ISC signal is a partial response signal.