A reception apparatus includes a detection unit that detects occurrence of a phase slip in phase estimation values of time-series received symbol data, and determines an inclination of the phase slip, a delay processing unit that generates first received signal data obtained by delaying received signal data obtained from the time-series received symbol data by one symbol time interval, a phase shift unit that generates second received signal data by performing phase shift according to the inclination, only in a period in which one symbol time interval elapses, on only the received signal data of a symbol time at which the occurrence of the phase slip is detected among pieces of the received signal data, and a remainder processing unit that derives a remainder of a difference between the second received signal data and the first received signal data.

A reception apparatus includes a detection unit that detects occurrence of a phase slip in phase estimation values of time-series received symbol data, and determines an inclination of the phase slip, a delay processing unit that generates first received signal data obtained by delaying received signal data obtained from the time-series received symbol data by one symbol time interval, a phase shift unit that generates second received signal data by performing phase shift according to the inclination, only in a period in which one symbol time interval elapses, on only the received signal data of a symbol time at which the occurrence of the phase slip is detected among pieces of the received signal data, and a remainder processing unit that derives a remainder of a difference between the second received signal data and the first received signal data.

The present disclosure relates to a pre-5.sup.th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4.sup.th-Generation (4G) communication system such as long term evolution (LTE). Methods and systems for optimizing computation of log-likelihood ratio (LLR) for decoding modulated symbols. A method disclosed herein involves receiving at least one symbol transmitted from at least one device, wherein the received at least one symbol is encoded and modulated symbol including a plurality of data bits. The method further includes computing a log-likelihood ratio (LLR) of each bit in the received at least one symbol for decoding the received at least one symbol using a centroid method that involves exploiting a symmetry of a constellation of code words and/or a uncertainty region defined on a constellation of code words.

As 5G, and especially 6G, push into ever-higher frequencies, phase noise presents an increasing problem. Disclosed are procedures and modulation schemes to mitigate phase noise and permit messaging at higher frequencies. Each modulation scheme provides phase-noise immunity by configuring modulation states with large phase acceptance regions. A message element is faulted if its sum-signal amplitude or phase is in an exclusion zone. Modulation schemes with fewer phase levels, more amplitude levels, and very broad phase acceptance regions are necessary for high frequency operation where phase noise dominates. Using allowed states with the maximum amplitude modulation in both branches can provide nearly 90-degree phase acceptance. Requiring that the two branches be equal provides nearly 180-degree phase acceptance. Further requiring that the amplitude levels be positive can provide total phase-noise immunity, with a 360-degree allowable phase range. Embodiments can thereby enable high frequency communication despite phase noise.

A method is disclosed for mitigating phase noise at high frequencies in 5G and 6G. Quadrature modulation schemes, in which orthogonal branches are amplitude modulated, are susceptible to phase noise which rotates the branches, causing demodulation faults. Disclosed is a single-branch reference signal that can mitigate phase noise. The transmitter can transmit a particular resource element having a normal amplitude in one branch, and zero amplitude in the orthogonal branch. The receiver can then measure the amplitudes of the particular resource element as-received (with phase noise), and determine a phase rotation angle according to a ratio of the two branch amplitudes. The receiver can then correct the branch amplitudes of each message element, and thereby negate the effect of the phase noise. The disclosed procedures can thereby make high-frequency, high-reliability communication feasible, at extremely low cost.

A communication system includes a demodulator configured to demodulate a modulated signal responsive to a first carrier signal. The demodulator includes a filter and a gain adjusting circuit. The filter is configured to generate a filtered first signal based on a first signal. The first signal is a product of the first carrier signal and the modulated signal. The filter has a gain adjusted based on a set of control signals. The gain adjusting circuit is coupled to the filter, and is configured to generate the set of control signals based on at least a voltage of the filtered first signal. The gain adjusting circuit includes a first peak detector coupled to the filter. The first peak detector is configured to output a peak value of the voltage of the filtered first signal.

A communication system includes a demodulator configured to demodulate a modulated signal responsive to a first carrier signal. The demodulator includes a filter and a gain adjusting circuit. The filter is configured to generate a filtered first signal based on a first signal. The first signal is a product of the first carrier signal and the modulated signal. The filter has a gain adjusted based on a set of control signals. The gain adjusting circuit is coupled to the filter, and is configured to generate the set of control signals based on at least a voltage of the filtered first signal. The gain adjusting circuit includes a first peak detector coupled to the filter. The first peak detector is configured to output a peak value of the voltage of the filtered first signal.

A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the code rate, a non-uniform constellation from one or several groupsof constellations each comprising one or more constellations.

A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the code rate, a non-uniform constellation from one or several groupsof constellations each comprising one or more constellations.

The disclosure relates to an IQ mismatch correction module for a radio receiver, the IQ mismatch correction module comprising: an input terminal configured to receive an input signal; an output terminal configured to provide a filtered output signal; a mismatch detection module comprising: one or more bandpass filters configured to receive, from the input terminal or output terminal, a bandpass input signal and to pass a plurality of sub-bands of the bandpass input signal to provide respective bandpass filtered signals; one or more amplitude and phase mismatch detectors configured to determine amplitude and phase mismatch coefficients based on the bandpass filtered signals from the plurality of sub-bands; a transformation unit configured to apply a transformation to the amplitude and phase mismatch coefficients to provide correction filter coefficients for the plurality of sub-bands; and a filter module configured to: receive the filter coefficients for the plurality of sub-bands from the mismatch detection module; and filter the input signal in accordance with the received filter coefficients to provide the filtered output signal.