Systems, methods, and devices reduce and mitigate spurs that may occur in transmit waveforms of wireless communications devices. Methods include receiving a plurality of samples of a baseband transmission and generating, using a processing device, an estimated amplitude and an estimated phase of a spur component of the baseband transmission based on the received plurality of samples, the spur component being a spectral spike in a transmit waveform. Methods further include generating, using the processing device, a canceling signal configured to cancel the estimated amplitude and estimated phase of the spur component, and canceling the spur component of the baseband transmission by combining the canceling signal with a transmission of at least a portion of a data packet.

Systems, methods, and devices reduce and mitigate spurs that may occur in transmit waveforms of wireless communications devices. Methods include receiving a plurality of samples of a baseband transmission and generating, using a processing device, an estimated amplitude and an estimated phase of a spur component of the baseband transmission based on the received plurality of samples, the spur component being a spectral spike in a transmit waveform. Methods further include generating, using the processing device, a canceling signal configured to cancel the estimated amplitude and estimated phase of the spur component, and canceling the spur component of the baseband transmission by combining the canceling signal with a transmission of at least a portion of a data packet.

An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.

An optical transmission method for processing a signal based on direct detection includes setting, by an equalizer, an adaptive equalization coefficient by performing an equalization process during a training symbol field section in a frame of a received signal, performing, by a channel estimator, channel estimation to perform an equalization process of a soft output maximum likelihood sequence equalizer (MLSE) during the training symbol field section, driving the soft output MLSE, and compensating for, by the soft output MLSE, distortion of the received signal during a data symbol field section in the frame on the basis of the adaptive equalization coefficient and an estimated result value of a channel, and recovering, by an error corrector which allows soft-decision processing to be performed, the received signal by performing error correction on the received signal in which the distortion is compensated for.

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.

Embodiments of systems and methods for wireless communication are disclosed. The method includes receiving a first payload, corresponding to original data, and demodulating a first payload estimation based on making a first soft decision of the first payload. The method also includes demodulating a second payload estimation based on making a second soft decision of the second payload and determining a first consolidated payload estimation based on consolidating the first payload estimation and the second payload estimation.

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.

Systems, methods, and devices reduce and mitigate spurs that may occur in transmit waveforms of wireless communications devices. Methods include receiving a plurality of samples of a baseband transmission and generating, using a processing device, an estimated amplitude and an estimated phase of a spur component of the baseband transmission based on the received plurality of samples, the spur component being a spectral spike in a transmit waveform. Methods further include generating, using the processing device, a canceling signal configured to cancel the estimated amplitude and estimated phase of the spur component, and canceling the spur component of the baseband transmission by combining the canceling signal with a transmission of at least a portion of a data packet.

Introduced here is at least one technique to better estimate interference at a receiver. The technique includes receiving a plurality of reference signals, which each have information indicative of noise. Thus, the technique further includes, for each reference signal, determining a noise estimation and determining a distance metric and log-likelihood ratio (LLR) of the noise estimation. Once the distance metric and LLR of each reference signal is determined, the receiver can determine a final LLR based on the distance metric and LLR of each reference signal. In this manner, a final LLR is determined. This technique can be applied by any device operating on MIMO technology.

A communication system and method are disclosed for parallel processing of received signals to improve sensitivity of the system. Generally, the method includes demodulating a modulated signal in a first demodulator circuit and a second demodulator circuit in parallel. The first and second demodulated signals are then de-whitened, and a cyclic redundancy code (CRC) check performed on each. If the de-whitened first demodulated signal passes the CRC check a first packet included in the signal is sent to a central processing unit (CPU) for further processing. If the de-whitened second demodulated signal passes the CRC check, and the de-whitened first demodulated signal fails, a second packet included in the de-whitened second demodulated signal is transmitted to the CPU for further processing. In one embodiment, one of demodulator circuits is a GFSK demodulator operated in the phase domain and configured to use maximum likelihood sequence estimation. Other embodiments are also described.