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.

A receiver embodiment has an equalizer that includes: an array of sample and hold elements, an array of linear equalizers, and an array of decision elements. Each sample and hold element in the array periodically samples an analog receive signal with a respective phase to provide an associated held signal. Each linear equalizer in the array forms a periodically-updated weighted sum of the held signals from the array of sample and hold elements. Each decision element in the array derives at least one sequence of symbol decisions based on at least one of the periodically-updated weighted sums. The resulting sequences of symbol decisions are output in parallel.

An iterative two dimension equalizer usable in a receiver of orthogonal time frequency space (OTFS) modulated signals is described. In one configuration of the equalizer, a forward path generates, from received time-frequency domain samples and a channel estimate, estimates of data bits and likelihood numbers associated with the estimates of data bits, generated by delay-Doppler domain processing. In the feedback direction, the estimates of data bits are used to generate symbol estimates and autocorrelation matrix estimate in the time domain. In another configuration, a soft symbol mapper is used in the feedback direction for directly generating the feedback input symbol estimate without having to generate estimates of data bits.

Provided are an apparatus and method for a sending end and a receiving end of a wireless communication system, and a soft information estimator. The apparatus for the sending end of the wireless communication system comprises: an interleave division multiple access unit configured to perform interleave processing on information to be sent; and a filter bank multi-carrier unit configured to use a specific sub-carrier chosen in advance to transmit the interleaved information in a parallel manner.

A radio communication system includes a radio apparatus and a signal processing apparatus that function as a base station, and the radio apparatus includes a channel estimation unit that, on the basis of a radio signal transmitted from a terminal apparatus, estimates channel information relating to a radio transmission path between the radio apparatus and the terminal apparatus; a demodulation unit that performs soft-decision demodulation of the radio signal on the basis of the channel information estimated by the channel estimation unit; a signal switching unit that, depending on the terminal apparatus that transmitted the radio signal, switches an output destination of a log likelihood ratio obtained by the soft-decision modulation between either a first path passing through a decoding unit that decodes the log likelihood ratio or a second path not passing through the decoding unit; and a transmission unit that transmits a signal output from the first path or the second path to the signal processing apparatus.

An equalizer includes a first feed-forward stage that provides a measure of low-frequency ISI and a second feed-forward stage that includes a cascade of stages each making an ISI estimate. The ISI estimate from each stage is further equalized by application of the measures of low-frequency ISI from the first feed-forward stage and fed to the next in the cascade of stages. The ISI estimates from the stages thus become progressively more accurate. The number of stages applied to a given signal can be optimized to achieve a suitably low bit-error rate. Power is saved by disabling stages which are not required to meet that goal.

A wireless communication device configured to select a spatial stream among a plurality of spatial streams, the plurality of spatial streams being included in a received signal vector, the received signal vector being associated with a symbol constellation, calculate a plurality of distance values, each distance value representing a distance between the selected spatial stream and a different hypothesis symbol among a plurality of hypothesis symbols, the plurality of hypothesis symbols corresponding to the symbol constellation, repeat the selection and the calculation for all spatial streams among the plurality of spatial streams not previously selected, and determine a detected symbol of each spatial stream among the plurality of spatial streams based on the plurality of distance values calculated for the plurality of spatial streams.

In certain embodiments, a method may include receiving one or more equalized samples of an input signal. The method may further include mitigating one or more excursions in the one or more equalized samples based on one or more current decisions of an iterative decoding process to generate compensated equalized samples. In addition, the method may include performing iterative decoding operations based on the compensated equalized samples, updating the current decisions of the iterative decoding process and outputting the current decisions as a converged result when the iterative decoding operations have converged for the compensated equalized samples.

A wireless communication device configured to select a spatial stream among a plurality of spatial streams, the plurality of spatial streams being included in a received signal vector, the received signal vector being associated with a symbol constellation, calculate a plurality of distance values, each distance value representing a distance between the selected spatial stream and a different hypothesis symbol among a plurality of hypothesis symbols, the plurality of hypothesis symbols corresponding to the symbol constellation, repeat the selection and the calculation for all spatial streams among the plurality of spatial streams not previously selected, and determine a detected symbol of each spatial stream among the plurality of spatial streams based on the plurality of distance values calculated for the plurality of spatial streams.

An apparatus including at least one processor configured to execute instructions and cause the apparatus to perform, obtaining for a first possible state (s) of a received sample at the current time step (k), log-likelihood ratio, Ilr, values Ilr.sub.old,min, Ilr.sub.old,max of a first transmitted bit (b.sub.j), wherein, the Ilr values Ilr.sub.old,min, Ilr.sub.old,max are respectively associated with a most likely state and a less likely state related to a received sample at the previous time step (k?1); determining based on path metrics and branch metrics corresponding to the received sample at the current time step (k); a first parameter (Q) related to a difference between likelihoods of the most likely state and the less likely state; updating magnitude of the Ilr value Ilr.sub.old,min at least based on the Ilr value Ilr.sub.old,min, the Ilr value Ilr.sub.old,max, and the first parameter, to obtain an updated Ilr value Ilr.sub.old,updated.