Constant-envelope phase-optimized transmission methods and apparatus are disclosed. An example method includes determining initial values of modulation phases in a first quadrant, the modulation phases associated with binary codes to be transmitted; and optimizing the initial values to second values to enable a product of an objective function to be within a threshold value.

A demodulation device includes a phase rotation module, a phase adjustment module, a phase comparison module, and a reference signal generation module. The phase rotation module rotates phases of an I-Phase signal and a Q-Phase signal in a received signal of a multilevel PSK signal using a reference signal. The phase adjustment module adjusts the phases of the phase rotated I-Phase signal and the phase rotated Q-Phase signal output from the phase rotation module by multiplying the phases of the I-Phase signal and the Q-Phase signal with an integer value to generate a phase adjusted I-Phase signal and a phase adjusted Q-Phase signal. The phase comparison module compares the phase of the phase adjusted I-Phase signal with the phase of the phase adjusted Q-Phase signal to generate a phase comparison result. Also, the reference signal generation module generates a reference signal using the phase comparison result.

Methods and apparatuses for providing a signal sideband signal via one or more switching method or apparatus. Pulse width modulation is utilized and high efficiency of amplification is provided via a switch mode amplifier. DC restoration may provide for improved carrier suppression. Also subtraction of complementary pulse width modulated signals provides for a multiplier circuit or a multiplier function. A nonlinear carrier signal coupled to a pulsewidth modulator provides for improved amplitude modulation linearity and/or reduced sideband distortion.

An apparatus, and method therefor, relate generally to broadband IQ generation. In this apparatus, related generally to broadband in-phase and quadrature phase (IQ) generation, a divider circuit and a polyphase filter circuit are configured for receiving an oscillator output. The polyphase filter circuit is configured for polyphase filtering the oscillator output into a first quadrature output. The divider circuit is configured for dividing the oscillator output into a second quadrature output. A multiplexer circuit is coupled to the divider circuit and the polyphase filter circuit and configured for selecting either the first quadrature output or the second quadrature output as an IQ output based on a bandwidth of the oscillator output.

Some embodiments relate to systems and methods for communication of electronic signals. An example method includes receiving a first signal having a predetermined modulation. The example method includes generating a transmission for a second signal by superimposing the second signal on the modulation of the first signal by adjusting at least one of two phase states or two amplitude states of the modulation using a Reconfigurable Intelligent Surface (RIS). The example method also includes transmitting the second signal using hierarchical modulation, the predetermined modulation and the superimposed second signal on the predetermined modulation, wherein the first signal is transmitted at a higher data rate than the second signal.

Methods and systems for NN-based digital pre-distortion for digital envelope tracking power amplifiers. A computer-implemented method includes receiving a measure of a digital envelope at a digital pre-distortion module having a neural network (NN)-based digital pre-distortion structure for digital envelope tracking (DET), receiving a transmit signal at the digital pre-distortion module, inputting the measure of the digital envelope and the transmit signal into the NN-based digital pre-distortion structure to produce a pre-distorted transmit signal, adjusting nonlinearity compensation of a power amplifier based on the measure of the digital envelope, and using the adjusted nonlinearity compensation of the power amplifier to produce an output signal.

Methods and wireless communication devices for mode classification include configuring the wireless communication device to receive a wireless frame transmitted over an operating channel bandwidth, determine a frequency domain signal representing a plurality of symbols carried in the wireless frame, estimate a primary channel bandwidth for the wireless frame from the frequency domain signal, determine a bandwidth field in a signal field of the wireless frame, compare the primary channel bandwidth with the operating channel bandwidth, and a mode used to transmit the wireless frame based on the bandwidth field and the comparing result.