To reflect advantages of continuous phase modulation (CPM), the invention provides a low complexity transmitter and receiver to transmit and receive CPM signals and addresses a significant reduction in the CPM demodulator complexity, and is especially well-suited for large values of L, e.g., L3. The invention utilizes a linear filter front end as an integral part of the CPM demodulation process to reduce the ISI inherent in CPM transmit signal, and minimizes the influence of L in the reception process. To that end, the invention renders the complexity of a CPM demodulator non-exponentially dependent on L, and L only has a weak impact on the number of coefficients of the linear front end filters. Moreover, the invention provides a simple way of forming CPM signals for a digital communication transmitter using parallel Time Invariant Phase Encoders, which simplifies the production of CPM waveforms on software or hardware.

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.

This application discloses a soft value extraction method and device applicable to an OvXDM system, and the OvXDM system. In the method, waveform coding is performed on all symbols in a hard value sequence, to generate a predictive value after overlapped coding; the symbols in the hard value sequence are reversed one by one, and overlapped coding is performed on each reversed symbol and associated symbols before and after the reversed symbol, to generate a predictive value of the reversed symbol; and for each symbol in the hard value sequence, a soft value of the current symbol is calculated based on A(.sup.+1.sup.1), where A is a coefficient related to a channel type, .sup.+1=y.sub.rxy.sup.+1, and .sup.1=y.sub.rxy.sup.1.sup.2; if y.sup.+1 is a predictive value of the symbol obtained after overlapped coding and before reversing, y.sup.1 is a predictive value of the symbol obtained after overlapped coding and reversing; and y.sub.rx is a received signal sequence.

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.

Methods, systems, and devices for wireless communications are described. For instance, first one or more wireless devices may receive or obtain a set of reference signals from second one or more wireless devices. The first one or more wireless devices may estimate a set of channel state information parameters, where each channel state parameter is based on a respective reference signal of the set of reference signals. The first one or more wireless devices may output or transmit a set of transmissions, where each transmission of the set of transmissions is based on a different gain parameter of the set of gain parameters, where each gain parameter of the set of gain parameters is based on a different channel state information parameter, and where each gain parameter of the set of gain parameters is less than a first threshold and greater than a second threshold.

A receiver including an equalization component to receive a signal comprising a sequence of samples corresponding to symbols and generate an equalized signal with an estimated sequence of symbols corresponding to the signal. The receiver further includes a decision generation component to receive the equalized signal and generate, based on the equalized signal, a decision comprising a sequence of one or more bits that represent each symbol of the sequence of symbols and a confidence level corresponding to the decision.

The application relates to a receiving device for a communication system, where the receiving device includes a receiver configured to receive a Multiple-Input and Multiple-Output (MIMO) communication signal including a plurality of transmit symbols belonging to at least one complex-valued symbol constellation, a processing circuit configured to affine-transform the at least one complex-valued symbol constellation to obtain at least one affine-transformed complex-valued symbol constellation, compute a decision metric; based on the at least one affine-transformed complex-valued symbol constellation, detect the transmit symbols based on the computed decision metric.

A method, system, and apparatus are provided for computing soft bits in a non-linear MIMO detector which decodes a signal received at a plurality of receive antennas using channel estimate information and a decoding tree to produce output data for a bit estimation value which includes a maximum likelihood solution along with a naturally ordered vector identifying all explored node metrics and node indices, where soft bits are computed for each bit estimation value by determining a set of bit-masks through repetition and indexing operations applied on the explored node indices, masking the naturally ordered vector with the set of bit-masks to generate masked node metrics, determining candidate soft bit values by subtracting metrics of all nodes that form the maximum likelihood solution from the masked node metrics, and determining a final soft bit value by identifying which of the candidate soft bit values has a lowest value.

A technology is described for moderating output confidence of output soft information associated with a MIMO detector. An example method can include generating output soft-information that is a measure of likelihood that a subset of bit sequence permutations correctly represents a bit sequence extracted from a radio signal received by the MIMO detector. Calculating a distance of the subset of bit sequence permutations to the bit sequence extracted from the radio signal. Determining that the output confidence of the output soft-information warrants adjustment of the output confidence of the output soft-information based in part on the distance of the bit sequence extracted from the radio signal to the subset of bit sequence permutations. And adjusting the output confidence of the output soft-information based in part on the distance of the bit sequence extracted from the radio signal to the subset of bit sequence permutations using an adjustment technique.