A communication system includes a transmitter configured to transmit a modulated signal, a transmission line configured to carry the modulated signal, and a receiver coupled to the transmitter by the transmission line, and configured to receive the modulated signal. The transmitter includes a modulator configured to generate the modulated signal responsive to a data signal and a carrier signal. The receiver includes a demodulator configured to demodulate the modulated signal responsive to a first carrier signal. The demodulator includes a filter and a gain adjusting circuit configured to adjust a gain of the filter, and to generate the set of control signals based on a voltage of the filtered first signal and a voltage of the first signal. The gain adjusting circuit includes a first peak detector coupled to the filter, and configured to detect a peak value of the voltage of the filtered first signal.

A communication system includes a transmitter configured to transmit a modulated signal, a transmission line configured to carry the modulated signal, and a receiver coupled to the transmitter by the transmission line, and configured to receive the modulated signal. The transmitter includes a modulator configured to generate the modulated signal responsive to a data signal and a carrier signal. The receiver includes a demodulator configured to demodulate the modulated signal responsive to a first carrier signal. The demodulator includes a filter and a gain adjusting circuit configured to adjust a gain of the filter, and to generate the set of control signals based on a voltage of the filtered first signal and a voltage of the first signal. The gain adjusting circuit includes a first peak detector coupled to the filter, and configured to detect a peak value of the voltage of the filtered first signal.

Embodiments of systems and methods for modulating a downlink signals representative of a communication signal are provided herein. An example method comprises receiving an input signal; in a first one or more processing blocks in a one or more processors, performing a first modulation operation on first data packets of the input signal based on a modulation scheme for a receiver of the downlink signal; in a second one or more processing blocks in the one or more processors in parallel with the first one or more processing blocks, performing a second modulation operation on second data packets of the input signal based on the modulation scheme; and generating a waveform as the downlink signal based on performing the first and second modulation operations.

The present disclosure provides a method for transmitting and receiving in a wireless communication system and an apparatus therefore. Specifically, in a wireless communication system according to an embodiment of the present disclosure, there is provided a method for transmitting and receiving a signal by a receiving apparatus, the method includes receiving, from a transmitting apparatus, signals modulated based on a differential phase shift keying (DPSK) method through a plurality of reception paths, calculating a differential value in each reception path of the plurality of reception paths based on the received signals, and calculating reliability for the received signals, in which the reliability is proportional to a real value of a sum of the differential values in each reception path of the plurality of reception paths.

Disclosed are short-form demodulation reference signals configured to indicate certain modulation levels of a modulation scheme, from which a receiver can measure phase noise and amplitude noise in 5G/6G. A key feature of short-form demodulation references is resource efficiency. Examples include a demodulation reference occupying just one resource element, while providing the information needed to determine all of the modulation states of the modulation scheme, as well as the current noise factors. In one embodiment, the short-form demodulation reference may include two component signals with orthogonal phase, both being amplitude modulated by the transmitter according to a maximum amplitude level. The receiver can determine the phase noise from a ratio of the two received signal amplitudes, and the amplitude noise from the magnitude of the received waveform, thereby mitigating both amplitude noise and phase noise. The short-form demodulation reference can be added to each message for real-time noise mitigation.

An method of determining a symbol according to a phase difference between input signals input in order of time may include calculating a first phase difference between a phase of a first previous signal received prior to a target signal and a phase of a second previous signal received prior to the first previous signal; calculating a second phase difference between a phase of the target signal and the phase of the second previous signal; calculating target likelihoods based on the first phase difference and the second phase difference; and determining an expected phase difference between the target signal and the first previous signal or an expected symbol for the target signal, based on the target likelihoods.

Systems and methods for classifying radio frequency signal modulations include receiving, at a consolidated neural network, a complex quadrature vector of interest representative of a baseband signal derived from a radio frequency signal, generating multiple data representations of the vector of interest, providing each data representation to one of multiple parallel neural networks in the consolidated neural network, and receiving, from the consolidated neural network, a classification result for the baseband signal. The consolidated neural network may be trained to classify baseband signals with respect to known modulation types by receiving complex quadrature training vectors, each including samples of a baseband signal derived from a radio frequency signal of known modulation type, comparing a classification result for the training vector to the known modulation type to determine modulation classification performance, and modifying a configuration parameter of the consolidated neural network dependent on the determined modulation classification performance.

Systems and methods for classifying radio frequency signal modulations include receiving, at a consolidated neural network, a complex quadrature vector of interest representative of a baseband signal derived from a radio frequency signal, generating multiple data representations of the vector of interest, providing each data representation to one of multiple parallel neural networks in the consolidated neural network, and receiving, from the consolidated neural network, a classification result for the baseband signal. The consolidated neural network may be trained to classify baseband signals with respect to known modulation types by receiving complex quadrature training vectors, each including samples of a baseband signal derived from a radio frequency signal of known modulation type, comparing a classification result for the training vector to the known modulation type to determine modulation classification performance, and modifying a configuration parameter of the consolidated neural network dependent on the determined modulation classification performance.

The present invention provides a phase shift keying modulation method and a corresponding modulator, a phase shift keying demodulation method and a corresponding demodulator. The phase shift keying modulation method comprises: mapping a binary data stream to be modulated into a phase sequence comprising one or more phase symbols according to a predetermined phase shift keying modulation mode; modulating the phase symbol with a preset phase function to obtain a phase signal that changes continuously with time, wherein in each symbol cycle, a difference between a value of the phase signal at a beginning of the symbol cycle and a value of the phase signal at an end of the symbol cycle is equal to the phase symbol modulated in the symbol cycle; and obtaining a radio frequency signal by modulation based on the phase signal.

The present invention provides a phase shift keying modulation method and a corresponding modulator, a phase shift keying demodulation method and a corresponding demodulator. The phase shift keying modulation method comprises: mapping a binary data stream to be modulated into a phase sequence comprising one or more phase symbols according to a predetermined phase shift keying modulation mode; modulating the phase symbol with a preset phase function to obtain a phase signal that changes continuously with time, wherein in each symbol cycle, a difference between a value of the phase signal at a beginning of the symbol cycle and a value of the phase signal at an end of the symbol cycle is equal to the phase symbol modulated in the symbol cycle; and obtaining a radio frequency signal by modulation based on the phase signal.