The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). A method for operating a receiving device in a wireless communication system comprises determining inter-symbol interference between symbols in a received signal, determining a location of a receive detection window according to the inter-symbol interference, and demodulating the received signal based on the location of the receive detection window. A receiving device includes at least one transceiver, and at least one processor configured to determine inter-symbol interference between symbols in a received signal, determine a location of a receive detection window according to the inter-symbol interference, and demodulate the received signal based on the location of the receive detection window. A transmitting device includes at least one processor configured to estimate an equivalent channel frequency response based on characteristic information of a time-domain filter, estimate an inter-symbol interference based on the equivalent channel frequency response, and generate indication information regarding an adjustment of a location of a receive detection window.

A transmitter may comprise a symbol mapper circuit and operate in at least two modes. In a first mode, the number of symbols output by the mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter may be greater than the number of data-carrying subcarriers used to transmit the OFDM symbol. In a second mode, the number of symbols output by said mapper circuit per orthogonal frequency division multiplexing (OFDM) symbol transmitted by said transmitter is less than or equal to the number of data-carrying subcarriers used to transmit said OFDM symbol. The symbols output by the symbol mapper circuit may be N-QAM symbols. While the circuitry operates in the first mode, the symbols output by the mapper may be converted to physical subcarrier values via filtering and decimation prior to being input to an IFFT circuit.

Various examples are directed to systems and methods for wideband digital predistortion. A digital pre-distortion circuit may be programmed to receive a complex baseband signal and generate a pre-distorted signal. Generating the pre-distorted signal may comprise applying to the complex baseband signal a first correction for an N.sup.th order distortion of a power amplifier at an I.sup.th harmonic frequency zone centered at about an I.sup.th harmonic of a carrier frequency and applying to the complex baseband signal a second correction for the N.sup.th order distortion at a J.sup.th harmonic frequency zone centered at about a J.sup.th harmonic of the carrier frequency different than the I.sup.th harmonic of a carrier frequency.

An example system comprises a first antenna and a modem. The first antenna is configured to receive a signal from a transmitting radio frequency unit. The signal includes data and a known sequence. The modem is configured to retrieve the known sequence from the signal, transform the known sequence and the data into a frequency domain, calculate averages of groups of neighboring frequency points in the frequency domain to reduce the effect of nonlinear noise in the signal, the neighboring frequency points corresponding to the preamble in the frequency domain, compare the calculated averages to an expected frequency response in the frequency domain, determine a correction filter to apply to the data based on the comparison, apply the correction filter on the data in the frequency domain to create corrected data, transform the corrected data from the frequency domain to the time domain, and provide the data.

Receiver and method in a receiver, for receiving a signal from a transmitter in a wireless communication system, based on OFDM. The method comprises: receiving a plurality of signals y from the transmitter; determining a group T of REs for which the CEE is assumed to be constant; extracting the determined group T of REs, from the received signals y; computing noise and CEE covariance matrix R.sub.ww for the extracted T REs, initialised as: R.sub.ww=(N.sub.0+Mσ.sup.2)I; computing a MMSE filter W.sup.MMSE, based on the computed noise and CEE covariance matrix R.sub.ww; and obtaining an MMSE estimate {circumflex over (x)} of payload data x comprised in the received signals y, associated with the extracted T REs by applying the computed filter W.sup.MMSE to the extracted T REs of the received signals: {circumflex over (x)}=W.sup.MMSEy.

In one example aspect, a method is provided of preparing a symbol for transmission, the method comprising applying a window function to a symbol to generate a modified symbol, wherein a property of the window function is based on a channel length of a transmission channel over which the modified symbol is to be transmitted, and causing the modified symbol to be transmitted over the transmission channel.

Disclosed are a wireless communication base station device and a division number determination method that improves the frequency diversity effect while maintaining channel estimation accuracy regardless of the number of divisions in the frequency domain of a transmission signal from a wireless communication terminal device. A determination unit determines the number of divisions in the frequency domain of a transmission signal from a wireless communication terminal device. Here, the determination unit increases the number of divisions in the frequency domain of the transmission signal from the wireless communication terminal device as the number of pilot blocks included in the transmission signal increases. In addition, a scheduling unit schedules allocation to the frequency resources of the divided transmission signal according to the number of divisions determined by the determination unit.

A spectrally efficient multi-carrier communication apparatus with advanced features of carrier management. The apparatus is flexible to changes in the form of the sub-carrier and their location in frequency. This invention can use non-standard pulses at arbitrary frequencies providing a greater control of the carrier. The additional features can be used for spectral efficiency, to correct signal distortion or for privacy. Also disclosed is a novel multiplexing method that saves spectrum called Spectral Shape Division Multiplexing (SSDM), preferred embodiments of the transmitter and receiver. Two complementary algorithms help the invention excel among other existent methods. The disclosed algorithms can similarly be adapted to other systems. A correction method for spectrally efficiency is calibrated to all desired noise levels for maximum benefit. An iterative multi-carrier reduction method dramatically reduces the error on overlapped subcarriers.

Gain variations during a packet can lead to significant performance degradation in communications systems that use high order quadrature amplitude modulation (QAM). A method and the associated apparatus track such variations in an OFDM system and completely eliminate any performance degradation. Gain estimation and compensation is employed with the use of pilot subcarriers in the payload of an OFDM data packet. Estimated pilot magnitude ratios are averaged, throughout the processing life of a packet, to yield accurate gain estimations. A gain compensation factor is used to adjust data carriers. An exclusion method is also employed to eliminate pilot carriers which contribute to noise.

The present invention concerns a method and device for transferring, by an emitter, a flow of samples to a receiver through a wireless interface using Single-Carrier Frequency Division Multiple Access. The emitter: —selects consecutive blocks of M samples of the flow of samples, —modulates each selected block, —selects, for each modulated block, half of the modulated block located in the center of the modulated block, —selects, with a M/2 sample shift, consecutive blocks of M samples, —modulates each selected block with the shift, —selects, for each modulated block with the shift, half of the modulated block with the shift located in the center of the modulated block with the shift, —forms a stream composed of one in two half ordered modulated blocks and, between two half ordered modulated blocks, one half ordered modulated block with the shift, —transfers the formed stream.