Systems (400) and methods for reducing a number of cyclostationary features in a transmitted signal. The methods comprise: obtaining by a transmitter a discrete-time IF signal comprising a sequence of samples all having a same sample duration; performing operations by a sub-sample dithering processing device of the transmitter to modify a sample timing of the discrete-time IF signal by decreasing or increasing a duration of at least one first sample of the sequence using a digital signal processing technique in a digital domain; converting the discrete-time IF signal to an RF signal; and transmitting the RF signal having a reduced number of cyclo stationary features.

Systems (400) and methods for removing dither introduced into a transmitted RF signal. The method comprising: receiving, by a receiver, the transmitted RF signal; converting, by the receiver, the transmitted RF signal into a discrete-time IF signal comprising a sequence of samples, where at least a first sample of said samples has a first sample duration different than a second sample duration of at least a second sample of said samples; and performing operations by a sub-sample dither removal device of the receiver to modify a sample timing of the discrete-time IF signal by decreasing or increasing the first sample duration of the first sample using a digital signal processing technique in a digital domain.

Disclosed in the embodiments of the present application are a data modulating and demodulating method, a data transmission method and node for multi-carrier system. The data modulating method including: selecting, by a transmitting node, corresponding waveform functions based on values of a first parameter, wherein the first parameter includes K values corresponding to K different waveform functions, respectively, and K is an integer greater than 1; and performing, by the transmitting node, using the selected waveform functions, modulation on time domain data sequences processed by Inverse Fast Fourier Transform (IFFT) to obtain a modulated data sequence. The first parameter may be configured by a base station for a UE. Also provided by the embodiments of the present application are a corresponding demodulation method and data transmission method and node.

A method is provided for modulating data symbols, outputting a multi-carrier signal, implementing: a mathematical transform, which transforms data symbols from the frequency domain to a time domain, outputting transformed symbols; and a polyphase filtering, which filters the transformed symbols, outputting the multi-carrier signal. The polyphase filtering uses an expansion factor taking account of a compression factor , the compression factor being a number between 0 and 1 such that the multi-carrier signal can be transmitted at a Faster-Than-Nyquist rate.

A resource block (RB)-based multicarrier modulation (MCM) transmitter and receiver structure for spectral agile systems are disclosed. The transmitter and the receiver are capable of sharing opportunistically available and non-contiguous channels with other users. The RB-MCM partitions the available spectrum, contiguous or non-contiguous, into multiple RBs (same or different sizes), applies a baseband MCM or single carrier modulation, or coded single carrier or multicarrier schemes in each RB with a type of spectral leakage reduction technique, and applies RB modulation for each RB to modulate the signal from baseband to the frequency band of that RB. At the receiver, the received signal may be filtered and RB demodulation may be applied to put each RB signal in baseband and a baseband multicarrier or single carrier or coded single carrier or coded multicarrier demodulation may be applied to each RB signal. Different RBs may use different modulation schemes.

A method is provided for receiving an OQAM multi-carrier signal, which implements a step of estimating, in the time domain, at least one time, phase, and/or frequency shift of the multi-carrier signal. The estimation step implements at least one estimator in order to estimate the time shift, referred to as a time estimator, and/or at least one estimator for estimating the phase shift, referred to as a phase estimator, and/or at least one estimator for estimating the frequency shift, referred to as a frequency estimator. The multi-carrier signal includes at least one preamble, and at least one of the estimators takes into account coefficients of a prototype filter used in transmission in order to shape at least one preamble inserted into the multi-carrier signal.

A resource block (RB)-based multicarrier modulation (MCM) transmitter and receiver structure for spectral agile systems are disclosed. The transmitter and the receiver are capable of sharing opportunistically available and non-contiguous channels with other users. The RB-MCM partitions the available spectrum, contiguous or non-contiguous, into multiple RBs (same or different sizes), applies a baseband MCM or single carrier modulation, or coded single carrier or multicarrier schemes in each RB with a type of spectral leakage reduction technique, and applies RB modulation for each RB to modulate the signal from baseband to the frequency band of that RB. At the receiver, the received signal may be filtered and RB demodulation may be applied to put each RB signal in baseband and a baseband multicarrier or single carrier or coded single carrier or coded multicarrier demodulation may be applied to each RB signal. Different RBs may use different modulation schemes.

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.