Adaptive non-linear model for highly-spectrally-efficient communications
A receiver may be operable to generate estimates of transmitted symbols using a sequence estimation process that may incorporate a non-linear model. The non-linear model may be adapted by the receiver based on particular communication information that may be indicative of non-linearity experienced by the transmitted symbols. The receiver may generate a reconstructed signal from the estimates of the transmitted symbols. The receiver may adapt the non-linear model based on values of an error signal generated from the reconstructed signal, and the values of the error signal may be generated from a portion of the generated estimates that may correspond to known symbols and/or information symbols. The values of the error signal corresponding to the known symbols may be given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols may be given less weight in the adaptation algorithm.
1. A method, comprising:
in a receiver:
generating estimates of transmitted symbols using a non-linear model;
adapting the non-linear model based on particular communication information that is indicative of non-linearity experienced by the transmitted symbols; and
generating, using the non-linear model, a reconstructed inter-symbol correlated (ISC) signal from the generated estimates of the transmitted symbols.
2. The method according to claim 1 , wherein the reconstructed ISC signal comprises a partial response signal.
3. The method according to claim 1 , comprising adapting the non-linear model based on values of an error signal generated from the reconstructed ISC signal, wherein the values of the error signal are generated from a portion of the generated estimates that correspond to known symbols and/or information symbols.
4. The method according to claim 3 , wherein the known symbols comprise pilot symbols and/or preamble symbols.
5. The method according to claim 1 , comprising adapting the non-linear model based on values of an error signal generated from the reconstructed ISC signal, wherein:
the values of the error signal are generated from a portion of the generated estimates that correspond to both known symbols and information symbols; and
the values of the error signal corresponding to the known symbols are given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols are given less weight in the adaptation algorithm.
6. The method according to claim 1 , wherein:
the particular communication information comprises one or more of the following:
a power level at which the transmitted symbols were transmitted, a condition of a channel via which the transmitted symbols were received by the receiver, a configuration of modulation used in transmitting the transmitted symbols, a performance indicator measured in the receiver, a received signal power level, a frequency band of the channel via which the transmitted symbols were received, and a temperature measurement; and
the configuration of modulation comprises one or more of the following: bit rate, symbol rate, modulation order, modulation type, coding rate and pilot symbols rate.
7. The method according to claim 6 , wherein the power level at which the transmitted symbols were transmitted is determined using an adaptive transmit power control (ATPC) algorithm and/or protocol.
8. The method according to claim 6 , comprising performing the adapting in response to:
measuring the performance indicator; and
determining that the measured performance indicator is below a threshold.
9. The method according to claim 1 , wherein how often the adapting is performed is determined based on the particular communication information.
10. The method according to claim 1 , comprising adapting the non-linear model continuously at a certain configurable rate that is fast enough comparing to a non-linear behavior variation rate.
11. The method according to claim 1 , comprising:
receiving at least a portion of the particular communication information via a control channel between a transmitter and the receiver; and
determining a bandwidth (BW) of the control channel based on the particular communication information.
12. The method according to claim 11 , comprising receiving indications of transmitted power level changes, indications of modulation type changes and/or indications of modulation order changes via an ATPC process or an adaptive code and modulation (ACM) process to save the BW of the control channel.
13. A system, comprising:
a receiver, wherein the receiver is operable to:
generate estimates of transmitted symbols using a non-linear model;
adapt the non-linear model based on particular communication information that is indicative of non-linearity experienced by the transmitted symbols; and
generate, using the non-linear model, a reconstructed inter-symbol correlated (ISC) signal from the estimates of the transmitted symbols.
14. The system according to claim 13 , wherein the receiver is operable to adapt the non-linear model based on values of an error signal generated from the reconstructed ISC signal, wherein:
the values of the error signal are generated from a portion of the generated estimates that correspond to both known symbols and information symbols; and
the values of the error signal corresponding to the known symbols are given more weight in an adaptation algorithm, and the values of the error signal corresponding to the information symbols are given less weight in the adaptation algorithm.
15. The system according to claim 13 , wherein:
the particular communication information comprises one or more of the following:
a power level at which the transmitted symbols were transmitted, a condition of a channel via which the transmitted symbols were received by the receiver, a configuration of modulation used in transmitting the transmitted symbols, a performance indicator measured in the receiver, a received signal power level, a frequency band of the channel via which the transmitted symbols were received, and a temperature measurement; and
the configuration of modulation comprises one or more of the following: bit rate, symbol rate, modulation order, modulation type, coding rate and pilot symbols rate.
16. The system according to claim 13 , wherein the receiver is operable to adapt the non-linear model continuously at a certain configurable rate that is fast enough comparing to a non-linear behavior variation rate.
17. A method, comprising:
in a receiver:
generating estimates of transmitted symbols using a non-linear model;
adapting the non-linear model via an adaptation algorithm that receives, as inputs, particular communication information and values of an error signal generated by the receiver, wherein:
the particular communication information is indicative of non-linearity experienced by the transmitted symbols;
the values of the error signal generated from a portion of the generated estimates that correspond to known symbols are given more weight in the adaptation algorithm; and
the values of the error signal generated from a portion of the generated estimates that correspond to information symbols are given less weight in the adaptation algorithm.
18. The system according to claim 13 , wherein the reconstructed ISC signal comprises a partial response signal.
19. The system according to claim 13 , wherein:
the receiver is operable to adapt the non-linear model based on values of an error signal generated from the reconstructed ISC signal; and
the values of the error signal are generated from a portion of the generated estimates that correspond to known symbols and/or information symbols.
20. The system according to claim 19 , wherein the known symbols comprise pilot symbols and/or preamble symbols.