Abstract: Apparatus and methods are provided for noise-whitening post-compensation in a receiver. A first apparatus includes a first whitening filter configured to filter a received signal comprising symbols to generate a first filtered signal. The first apparatus further includes a first decision feedback equalizer having an input coupled to an output of the first whitening filter to receive the first filtered signal. The first decision feedback equalizer is configured to apply decision feedback equalization to the first filtered signal to generate estimates for the symbols of the received signal. A second apparatus includes a decision device configured to generate a symbols decision based on a received signal comprising symbols, a noise predictor configured to predict noise in the received signal, and a subtractor configured to subtract the predicted noise from the received signal to generate a symbols estimate.

Abstract: Apparatus and methods are provided for noise-whitening post-compensation in a receiver. A first apparatus includes a first whitening filter configured to filter a received signal comprising symbols to generate a first filtered signal. The first apparatus further includes a first decision feedback equalizer having an input coupled to an output of the first whitening filter to receive the first filtered signal. The first decision feedback equalizer is configured to apply decision feedback equalization to the first filtered signal to generate estimates for the symbols of the received signal. A second apparatus includes a decision device configured to generate a symbols decision based on a received signal comprising symbols, a noise predictor configured to predict noise in the received signal, and a subtractor configured to subtract the predicted noise from the received signal to generate a symbols estimate.

Abstract: A symbol detection and forward error correction (FEC) decoding system and method are disclosed that aim to increase decoding performance and maintain an acceptable level of complexity. In one embodiment, the method includes performing detection and decoding over a plurality of iterations. During the first iteration: a first equalizer structure processes a received signal, and a FEC decoder performs decoding on an input obtained from the output of the first equalizer structure. During the other iterations: an iterative equalizer structure processes both (i) the received signal and (ii) an input obtained from an output of the FEC decoder from a previous iteration of the detection and decoding, in order to generate an output of the iterative equalizer structure, and the FEC decoder performs FEC decoding on an input obtained from the output of the iterative equalizer structure.

Abstract: Systems and methods are disclosed that attempt to increase spectral efficiency by using Faster-than-Nyquist (FTN) transmission. In one embodiment, a method at a transmitter includes partitioning bits into K bit streams, obtaining K power scaled symbol streams, combining the K power scaled symbol streams to obtain a stream of transmission symbols, and transmitting the stream of transmission symbols using FTN signaling. At the receiver, the received symbols are partitioned into K symbol streams, and demodulation and decoding is performed by: (i) demodulating and decoding the Kth symbol stream of the K symbol streams to obtain a Kth set of bits; (ii) mapping the Kth set of bits to a Kth set of symbols; and (iii) for each one of k=K?1, . . . , 1: demodulating and decoding a kth symbol stream of the K symbol streams to obtain a kth set of bits. The demodulating and decoding includes performing interference cancellation.

Abstract: Systems and methods of precoded faster than Nyquist (FTN) signalling are provided. In the transmitter, Tomlinson-Harashima Preceding (THP) is applied to produce precoded symbols. The THP is based on inter-symbol interference (ISI) due to using faster than Nyquist (FTN) signalling. An inverse modulo operation is not performed in the receiver. Instead, in the receiver, FTN processing is performed based on a matched filter output by determining log a-posteriori probability ratio LAPPR values computed for an nth bit bn of a kth received symbol and pre-computed a-priori probabilities of an extended constellation for a given pulse shape h(t) and FTN acceleration factor combination.

Abstract: Systems and methods of precoded faster than Nyquist (FTN) signalling are provided. In the transmitter, Tomlinson-Harashima Preceding (THP) is applied to produce precoded symbols. The THP is based on inter-symbol interference (ISI) due to using faster than Nyquist (FTN) signalling. An inverse modulo operation is not performed in the receiver. Instead, in the receiver, FTN processing is performed based on a matched filter output by determining log a-posteriori probability ratio LAPPR values computed for an nth bit bn of a kth received symbol and pre-computed a-priori probabilities of an extended constellation for a given pulse shape h(t) and FTN acceleration factor combination.

Abstract: Systems and methods are disclosed that attempt to increase spectral efficiency by using Faster-than-Nyquist (FTN) transmission. In one embodiment, a method at a transmitter includes partitioning bits into K bit streams, obtaining K power scaled symbol streams, combining the K power scaled symbol streams to obtain a stream of transmission symbols, and transmitting the stream of transmission symbols using FTN signaling. At the receiver, the received symbols are partitioned into K symbol streams, and demodulation and decoding is performed by: (i) demodulating and decoding the Kth symbol stream of the K symbol streams to obtain a Kth set of bits; (ii) mapping the Kth set of bits to a Kth set of symbols; and (iii) for each one of k=K?1, . . . , 1: demodulating and decoding a kth symbol stream of the K symbol streams to obtain a kth set of bits. The demodulating and decoding includes performing interference cancellation.