A method for transmitting a signal is described, wherein the method has transforming a signal into a frequency domain to obtain a spectrum, forming a filtered spectrum according to a filter spectrum and occupying a set of subcarriers of a frequency domain representation of an Orthogonal Frequency Division Multiplex (OFDM) signal with the filtered spectrum. A temporary signal is obtained by transforming the frequency domain representation of the OFDM signal into a time domain. The temporary signal is subjected to a phase modulation.

Disclosed are a roll-off period detection method, a symbol starting point detection method, a fractional frequency offset estimating method, and an OFDM downstream system using the same. A method of detecting a roll-off period in an OFDM downstream system according to an embodiment of the present disclosure may include: generating a temporary roll-off period by applying a windowing function to a signal having a preset length; and detecting a roll-off period based on any one of a cross correlation and a sum of differences between a detection target signal included in a range of two OFDM symbol signals based on a detection starting point, and the temporary roll-off period.

A method for transmitting a signal is described, wherein the method has transforming a signal into a frequency domain to obtain a spectrum, forming a filtered spectrum according to a filter spectrum and occupying a set of subcarriers of a frequency domain representation of an Orthogonal Frequency Division Multiplex (OFDM) signal with the filtered spectrum. A temporary signal is obtained by transforming the frequency domain representation of the OFDM signal into a time domain. The temporary signal is subjected to a phase modulation.

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 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.

Methods and apparatuses for PAPR reduction based on a pulse shaping operation in a wireless communication system. A method of operating a UE includes: converting, using a DFT, a modulated block of data symbols to a first symbol block in a frequency domain; extending, based on a spectral extension ratio associated with extended subcarriers (N.sub.se), the first symbol block to a second symbol block with a length that is identified based on a number of scheduled subcarriers (N.sub.SC), wherein the second symbol block is symmetrically extended DFT symbol block; generating, using an FDSS filter with a number of tap values (N.sub.P), third symbol block based on the second symbol block that is symmetrically extended DFT symbol block; mapping the generated third symbol block to the N.sub.SC; generating, based on the mapped third symbol block, OFDM symbols in a time domain using an IFFT; and transmitting, to a BS, signals including the OFDM symbols.

An apparatus for a receiver is provided, said apparatus comprising means for receiving an input signal, based on a frequency domain signal, means for performing deprecoding on the received input signal and means for providing the deprecoded signal as an input for a machine learning model, wherein the output of the machine learning model is a likelihood ratio.

An apparatus for a receiver is provided, said apparatus comprising means for receiving an input signal, based on a frequency domain signal, means for performing deprecoding on the received input signal and means for providing the deprecoded signal as an input for a machine learning model, wherein the output of the machine learning model is a likelihood ratio.

Apparatuses and methods for a sounding reference signal design and signaling in cellular communication systems. A method of a UE in a wireless communication system includes: receiving, from a base station (BS), a radio resource control (RRC) signal including first RRC parameters; identifying, based on the first RRC parameters, an aggregation flag indicating whether to enable sounding reference signal (SRS) slot aggregation; receiving the RRC signal including second RRC parameters indicating an SRS hopping pattern based on a determination that the SRS slot aggregation is enabled; performing, based on the SRS hopping pattern, the SRS slot aggregation to generate a super slot; and transmitting, to the BS, an SRS based on the super slot.