A receiver unit comprising a signal input configured to receive a receive signal including a plurality of data symbols, a symbol detection circuit configured to detect a subset of data symbols, a reliability measuring circuit configured to determine a reliability value for the data symbols, a feedback loop configured to detect the subset of data symbols and the reliability value iteratively, and a signal output circuitry configured to determine output values of the subset of data symbols on the basis of the detected subset of data symbols and the determined reliability value.

It is difficult to obtain a demodulated signal with high signal quality in a digital optical receiver because it is difficult to compensate for each of different types of waveform distortion by a high-performance equalization process; therefore, a digital signal processor according to an exemplary aspect of the present invention includes a fixed equalization means for performing a distortion compensation process based on a fixed equalization coefficient on an input digital signal; an adaptive equalization means for performing an adaptive distortion compensation process based on an adaptive equalization coefficient on an equalized digital signal output by the fixed equalization means; a low-speed signal generation means for generating a low-speed digital signal by intermittently extracting one of the input digital signal and the equalized digital signal; a low-speed equalization coefficient calculation means for calculating a low-speed equalization coefficient to be used for a distortion compensation process of the low-speed digital signal; and a fixed equalization coefficient calculation means for calculating the fixed equalization coefficient by using at least a predetermined coefficient out of the low-speed equalization coefficient and the predetermined coefficient.

A method of designing a digital filter for example for use in an FBMC/OQAM telecommunications system, with a target overlapping factor and meeting a specified signal to interference ratio is described, whereby a candidate filter design defined by an impulse response, satisfying the Nyquist criterion and having an overlapping factor higher than the target is selected, and the time and frequency coefficients of its impulse response inverted to define a new filter design; and

truncating the impulse response defining said new filter design to the minimum number of coefficients achieving said specified signal to interference ratio.

A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit.

An anti-aliasing channel estimation apparatus and method and a receiver where the anti-aliasing channel estimation method includes: performing clock recovery and data synchronization on a received multicarrier signal with channel aliasing, to obtain a synchronized time-domain signal and a sampling phase; calculating an estimation signal after passing through a channel and being aliased based on a training sequence and the sampling phase, and obtaining a channel response and an aliasing signal response of each subcarrier of the multicarrrier signal based on the estimation signal and the frequency-domain signal. Therefore, channel estimation may be performed on the multicarrier signal with channel aliasing, influence of the channel aliasing on the bit error rate may be lowered, and transmission quality of the system may be improved.

Apparatuses, methods, and systems are disclosed for data block transmissions. One method (1000) includes transmitting (1002) a data blocks frequency multiplexed in a time duration to a device, wherein: the data blocks are transmitted based on spatial information and a redundancy version sequence; each data block of the data blocks carries the same data varied based on a redundancy version indicated by the redundancy version sequence and occupies a same number of virtual resource blocks in a frequency domain; the data blocks are scheduled by a control channel, wherein the control channel is used to transmit information that indicates the redundancy version sequence of redundancy version sequences configured by high layer signaling; the spatial information is indicated in the control channel or is configured by high layer signaling; and a total number of data blocks of the data blocks is configured by high layer signaling.

Techniques are provided for tracking of signals. A methodology implementing the techniques according to an embodiment includes filtering a first segment of an input signal, associated with a first time interval, into a first plurality of frequency bins. The method also includes detecting a signal of interest (SOI) in one of the first plurality of frequency bins. The method further includes filtering a second segment of the input signal, associated with a second time interval, into a second plurality of frequency bins. The method further includes determining movement of the SOI from a first frequency bin, of the first plurality of frequency bins, to a second frequency bin, of the second plurality of frequency bins. The method further includes tracking the SOI based on the movement determination. In some cases, the method further includes creating a composite signal based on the tracking over multiple frequency bins and multiple time intervals.

Apparatuses, systems, and techniques to perform signal processing operations in a fifth generation (“5G”) radio signal. In at least one embodiment, one or more processors equalize, in parallel, one or more 5G radio signals.

A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.

A known pattern comparison type phase difference detection unit (12) detects a phase difference between a known pattern extracted from a received signal and a true value of the known pattern as a first phase difference. M indicates the number of modulation phases in a phase modulation method of the received signal. An M-th power type phase difference detection unit (13) removes a modulation component by raising the received signal to M-th power, and detects phase variation from a modulation phase point used for mapping on a transmission side, as a second phase difference. A phase compensation unit (11) compensates phase variation of the received signal based on an addition result of the first phase difference and the second phase difference.